Can anyone recommend any good coloured pens for drawing on glass? I want DDs to decorate various glass things for Christmas (a container for an orchid, and jars which I'm going to make scented candles in). Girls have just finished decorating some jars using Giotto Decor pens which I thought would work but it rubs/scratches off and looks pants 
. Not looking forward to telling them they need to start again...
Baker Ross/Yellow Moon do various types, but I'm not too keen to spend over £10 on some (with delivery) if they're no good, and their reviews are useless.