Is it normal to paint bottle tops with nail polish and/or pa?

Whenever I get a new colour of nail polish, I have to paint it onto a random bootle lid/lipstick container/nail polish bottle lid of some kind.

Some time after that, I'll paint my nails in the colour and/or paint all the shades of nail polish I own on a sheet of paper so I can see what colours I have and get rid of the old crap.