However, here is one of my ideas, I would like to call it a solution but it will probably be a temporary solution, kids are notorious for being untidy and have time to play but not for clean-up. Besides, kids should be kids and not have to worry about these things too much but a little nudging helps. But when my girls do tidy their room they are spotless, I love it.
They have a an art desk with draws but instead of placing the art materials in a orderly fashion it is all displaced and spread over several draws. So now we have a paper draw, a pen draw and paint draw and materials draw and these lovely little pots are for easy access for everyday needs, $1.25 each.