Adam gets a large amount of shampoo on his shirt and vest. A few minutes later he is completely clean. There is no way to remove that sort of material without a trace short of laundering the clothing it's on.
However he would have simply changed the soiled garments for fresh ones.
Jonah tells Isaac that if he quits after 3 pm then Cloud 9 has to pay him for a full day of work. Cloud 9 employees are all hourly, meaning they are paid for the amount of time worked, not per day worked. However Jonah is trying to get the temp to quit so he is lying to him.
When Adam is stocking the DVDs, the entire top row is filled with copies of a single title, as evidenced by their identical spine (whereas the surrounding shelves are all filled with a variety of different DVDs). While it could be a mistake on Adam's part, the fact that Amy is chastising him for not stocking properly but makes no mention of this gaff suggests it is a production error, rather than a character error.
Dina argues with Glenn that there is "no such thing" as a manager's parking spot. It was established in Demotion (2016) that not only is there a manager's parking spot, but the assistant store manager has an assigned spot right next to it. As Dina has been assistant store manager for a number of years at this point, there's no way she wouldn't have known she had her own assigned spot just as close to the store as the manager's.