How do I write in a birthday invitation (for my 3 yr old) for money toward my kid's college fund/ savings? ?

We are celebrating my daughter's 3rd birthday and I want to put in the invitations that we don't want any toys or clothes. I don't want to seem greedy, but my daughter has lots of clothes and toys. I don't need any more than she already has. I know that it is the thought that counts. But it would be nice for monetary gifts so I can save towards my daughter's college fund/ savings. How can I write that in an invitation without getting any negative thoughts or comments?