Teaching the value of toys/books

[littleraysofsunshine]

How do you in force this with preschooler age?

How do you mean exactly? With dd (nearly 3) if she is doing something inappropriate then I show or tell her how to use or do whatever it is properly. Eg if she is using colours somewhere she shouldn't be then I give her paper or a colouring book. Likewise if dd is standing on a book I ask her to pick it up if she wants me to read it or to put it away. If she ignores any of theese things then I remove the item. Ie I would take away colours until after lunch or the next day. Repeating if she does it again but for a longer period.

Show them how to put stuff away and have fewer things out.