Here is the original link I found: http://amanda0480.blogspot.ca/2011/05/recycling-old-and-crusty.html
All I did was use one marker and I stuck it in a small amount of water in a baby food jar. I left it for about 4 days and when the kids and I tried it out they worked like a charm! The colours aren't as deep as food colouring or actual water colours but for the frugal teacher this is a pin win! I am heading to Michaels this weekend to get some good quality water colour paper and will post pictures of our marker water colours this week!