We just put a small amount in an air tight container with a cotton bud and instructions. Although we try not to do this as you never know if the client will do the test and I did read that you may not be covered if the client reacts to the tint if you haven’t physically performed the test yourself! We only really do this to our regular clients
I wouldn't bother if I were you. People are so unreliable if not a little bit blase about our strict rules and insurance. For me it is a definate no no, I would not trust them to mix it and use it strictly by the book.
We are the professionals and our insurance is what keeps us from having to break our training protocol.
Sick to the rules is what I say ; Sorry If I have put a dampner on your plans.