Every mac store/counter I've been to sets out little glass beakers full of disposable q-tips (for e/s), doe foot applicators (for l/s), and brushes (for glosses and nail polishes). They also set out tissue and MAC wipes. I test products on the back of my hand only, using the q-tips they set out (or the applicators for the l/s so the little cotton pieces from the q-tips don't stick to the l/s). Then when my hand fills up I wipe it off and start over. I very rarely, if ever, try things on my face, even if they've been sanitized. I can usually tell by testing it on the back of my hand, and if you really hate it that much when you get home, there's always returns and/or swaps.