It started with a base of one part vinegar to two parts water with a quarter parts alcohol, each added in time while you stirred vigorously.  Pure ethanol worked best, but rubbing or isopropyl was just as effective if one didn't have time or money to create or purchase the pure distilled liquid. It did require a few extra minutes of stirring after all of the bases were combined, to ensure the solution was properly combined. He’d discovered that failing to do so made the area more easily stained later, a phenomenon that baffled him still. Once the base was thoroughly combined you had to light a hot fire under the cauldron, to bring it to a boil quickly. While you waited, you crushed and mixed one parts Quartz salt with 1 parts Sodium Bicarbonate. Then you sprinkled it in gently while stirring counterclockwise. He tisked and shook his hair out of his eyes as he worked over his mortar before he huffed and very quickly pulled it back with a tie. He was grateful that there was a large enough margin of error that this small pause would not ruin the batch completely. He watched the potion begin to foam and very quickly added a drop of Essence of Milkweed. He grin as the potion slowly turned that same, slight gross greenish-white colour it was supposed to. He lifted his spoon and confirmed with a grimace the slight stringy stickiness of the mixture. This stage always revolted him. He pulled down the jar of Demiguise saliva and grimaced. Then he took a measure of the slimy substance and drizzled it into the cauldron, first in a clockwise spiral then a counterclockwise one. Then he waited. Slowly the clear viscous liquid sunk into the potion. As it began to bubble he rolled up his sleeves, put on his dragonhide gloves, tilted the cauldron, and began to rapidly whisk the entire mixture. It was hard to do at first, and he had to be careful that not a drop of sweat landed in the solution, or it wouldn't work for sweat stains. But the more air he introduced the easier it became until he was staring at a rather revolting, when you thought of it, off-white meringue. He smiled again. Now this was the cool part! Using a beaker and a test tube, he tipped one thimble of crushed luna moth wings into two measures of lemon juice and swirled it again. As it fizzed and bubble he tipped the beaker into the cauldron. Instantly the potion let out a loud fizz. The whole thing sizzled and frothed. And went. The meringue was collapsing, and slowly losing its greenish hue. And finally, Harry looked down at the clear liquid inside the cauldron with a beaming smile. He looked down at the pair of jeans his mother had been complaining about earlier and took a small spoon and poured it on. The effect was instant. The potions soaked into the fabric, and the offending grass stain melted away. A quick drying charm and the fabric was completely unblemished as if it had never been stained in the first place.

“Ha ha!” Harry cried excitedly. Then quietly he heard a clap of hands. He looked over to his father with a cheeky grin.

“Very well done!” Severus cried. He looked at the ladle and frowned. “Slightly less viscous…”

“I used less demiguise spit,” he shuddered. “I hate that stuff. And I don't need as much as I originally thought. I wonder if your formula needs as much either? The stuff is not cheap! Nearly a whole galleon for this jar!” Harry complained, lifting the already almost empty half-gallon jar up to the light with a scowl. Severus let out a chuckle. “What?”

“You sound like me more and more every day,” Severus admitted. “I too spend an inordinate amount of time complaining about reagent prices.” Harry pulled a face before he let his hair down and scowled slightly.

“I need a haircut,” he complained. His expression was grim, which Severus knew was due to past experiences being unpleasant. “It always gets so unruly at this length! I never know what to do with it!”

“Conversely,” Severus began. “You could grow it out longer. I have a feeling that your hair will be much like mine if it grows longer.” Harry winced slightly as he heard that and Severus’s face went blank. “It will not be as greasy.”

“Erm,” Harry began with a slight blush. “Do you mind me asking… that is-”

“It is because of potions fumes. Excessive time around potions has been shown to negatively affect the pH balance of the skin, especially with repeated exposure to noxious or poisonous vapours. It is also why my skin is so clammy. One solution is to wear a cap, which many in the potions community do. I have yet to find a cap which doesn't make me look like either a 17th-century crusader or else a 16th-century bishop. Another solution would be to cut my hair exceedingly short. But I find it makes me look too militaristic for my tastes. The final solution is to bathe every time I leave the lab and apply a revolting number of skin care products all over my person. But as I spend up to ten cumulative hours a day in my lab, taking a break between each class and research session to wash my hair and apply products would be excessive and in the end pointless.” Severus lectured bitterly. “Especially with Longbottom there wreaking havoc…”

“Well, good news!” Harry argued. “This year is the last year you have to deal with Neville or he has to deal with you! He’s planning to drop potions after his owls.”

“Mercy of mercies!” Severus cried in relief. “Finally.”

“He wants to focus more on Herbology,” Harry explained as he went about cleaning up his workstation. Now that it was brewed the ‘Potter Stain Stopper’ (god he still hated that name) was perfectly stable and wouldn't begin to evaporate or spoil for at least a few hours. It would eventually, which is why the labels on their bottles instructed people to keep it closed when not in use, but it took a very long time. As he worked his father came up beside him and assisted, wiping down the pestle and mortar and various implements with practised expertise. Harry had watched his father work a few times now and was honestly astounded by how amazing he could be. Potions master indeed. 

“Indeed? Yes, I have noticed he seems to handle the plant portion of the reagent class quite well. He seems to know which part of the plant is used intrinsically.”

“He really liked plants.” Harry agreed. “Not just what they're used for, but how they grow, and what you need to do to make them the best they could possibly be. It's honestly amazing sometimes listening to him… and a bit annoying.” Harry finished with a wince.

“Annoying?”

“He says ‘amazing!’ a lot,” Harry said with a roll of his eyes. “A lot.”

“I see,” Severus said with a chuckle as he finished putting away the last of the unnecessary equipment. He pulled forward the case he had lent Harry, filled with the newly labelled potion vials and pulled one out, inspecting the label again.

Harry Potter’s Stain Stopper

Directions: Apply 1-3 drops onto the stain, wait for the potion to be absorbed, then apply drying charm. Safe for all fabric types. Works best on fresh stains.

“I feel as though that last line is a touch of false advertising,” Severus argued. “You know as well as I that the age of the stain has yet to have made a difference.”

“I know,” Harry agreed. “But Tracey says that it's smart to cover our bases. This stuff lasts for a long time. So it's possible people who bought it last year are trying it on old clothes they had at home with stains.”

“Harry, we tested it on my training apron from 1978!” Severus reminded him with a snort. “If it can remove stains from over 20 years ago, when none of your classmates were even alive, you can remove the line about fresh stains!”

“Alright!” Harry said with a huff. “I'll talk to Tracey about it.”

“Speaking of Miss Davies…” Severus began with a swallow. “How is she enjoying Japan?”

“She loves it,” Harry said casually. “She says that Kyoto is so much more beautiful than London. She went to Mount Fuji last week, she sent me a photo,” Harry reached into his back pocket and pulled it out and smiled. The girl was leaning on a fence, backdropped by a fantastic view of a massive mountain framed by bonsai and Japanese maples. Then she noticed the camera turned and gave it a beaming smile and a little wave. Severus watched Harry's own smile beam down at the little miniature of his girlfriend. Then he noticed a second photo behind it and quirked an eyebrow.

“What about the other one?” Harry blushed and tried to hide it.

“Erm… well,” Harry began with a swallow. Severus narrowed his eyes.

“Show me.” Harry blushed beet red but slowly revealed it. Severus' eyebrows shot up. It was another photo of Miss Davies, but her face was half hidden, with sultry eyes, behind a paper fan, which she was fluttering rather… suggestively. Her outfit was reminiscent of a traditional Japanese dress but less formal, in a light teal base covered in an orange and white koi fish pattern. Her hair was piled high on her head and was decorated with pale orange silk flowers.

“Her family was in Himeji a few days back. The family she was staying with decided to dress her up for the Yukata Festival.” Harry looked down at it again and blushed. “She er… said she posed just for me,” Severus grunted and thrust the photo back into his hands.

“I do hope I don't have to remind you of… certain dangers.”

“Oh god!” Harry cried in horror. “Please don't! Madam Pomfrey cornered everyone last year before the Yule Ball… it was awful!”

“Yes, well… good.” Severus choked out. The air became much too hot and embarrassing for Harry's liking and he quickly turned away, stuffing the photos back into his pocket.

“Let's just bottle this batch!” Harry said quickly. Severus cleared his throat and nodded. The pair went back to work in silence, for which Harry was exceedingly grateful.

Harry put the final period on the scroll he was holding and leaned back.

"I'm done." He declared, with an air of awe.

"Hmm?" Emmeline asked from beside him.

"I'm done with my summer homework!" He cried with a grin. "I actually managed to finish it all before my birthday!"

"Congratulations!" Severus cried before his voice gained a tone of sarcasm. "And here I thought it would be impossible to break your procrastination habits."

"Shush!" Harry argued back with a pout. "It wasn't procrastination! It was… habit." Harry finished with slight melancholy. Severus nodded with understanding and didn't say anything more. 

"So," Emmeline said, artfully steering the conversation. "What are you going to do with the rest of your free time?" Harry grinned. A whole month of free time!

"I'm going to train Snappy a bit more." Harry started. "Hagrid said he could be trained to fetch things and be used to keep things safe. Nothing too big, but still useful. I also want to get some flying in of course. Maybe I can visit the Weasleys," he looked to his parents who both gave nods which made him smile wider. "We'll need to go to Diagon Alley at some point for new school stuff. I think I need new robes again."

"You have shot up like a weed this year," Emmeline remarked with a sniff. Harry turned to see she had a somewhat heartbroken expression and smiled slightly. He leaned into her and she immediately pulled him in for a hug. Snuggled up against his mother he went back to his list. "Tracey won't be back until a week before Hogwarts so I'll have to wait to see her. Maybe I'll practise brewing some more!" He craned his neck to his dad with a questioning look. The man had a small prideful smile and nodded. Harry grinned and turned back.

"Careful Darling," Emmeline began warningly. "Your father had all but given up on you becoming a potions master. But you're starting to get his hopes up again." Harry blinked and turned to give his father a sheepishly apologetic look. Severus for his part didn't look the least bit ashamed

"I think I can convince you yet." Severus declared. Harry laughed.

"Sorry Dad, but I don't know about that," he shrugged. "Potions are cool, but Runes are fascinating… I think I want to become an artificer." He admitted candidly. His parents blinked in shock. Harry's expression twisted up. "Maybe… I really don't know."

"Well, this is the year you'll receive career counselling from your head of house," Severus explained casually. "She can help you figure out your best options. But I think you would enjoy being an artificer. Your Yule medallions are proof of your skill."

"Last year proved that if I had been wearing it properly I wouldn't have been as badly hurt during the train attack in your third year," Emmeline said candidly, referring to the charred remains of the medallion Harry had been wearing during the World Cup attack last year. Harry smiled and leaned into her for a hug.

"I guess I'll wait till McGonagall gives her advice." Harry finished with a sigh. Then he sat up with a grin. "Which means I don't have to worry about anything! No more stress!"

"Indeed," Severus agreed with a chuckle. "Just don't forget your chores." Harry's expression faltered a bit as his parents laughed at his expense.