Hmm I havent had any problems at all,. but I use liquid liners a whole lot,.. and the eyeliner mixing medium a lot which is thicker than most regular liquid liners,.. I do however usually use my own brush,.. I find that if I clean it immediately with my MAC brush cleaner after application,.. the liquidlast does come off,.. get it before it has time to set,... And as Shawna was tlaking about,. I have started tipping my lashes with them over my mascara,.. it looks really cool to have fuschia or aqua tipped lashes,.. got this idea from where it did get into my lashes the first time I tried to apply them.