Tax Credits and the Legal Situation

This is something I don't really know about. American tax law. My reading of it is that if we end up raising $ 10k or $ 15k then no one is going to worry very much. We'll be treated like a glorified bake sale or something.
However, if this story has legs and we start to get significant numbers, we'll have to register as a charity ourselves. We can't simply send ink jets off to recyclers and then get the money sent direct to the charity. On a large scale, there will be costs associated with sorting. Not just wages for sorters and things like packaging material, but also disposal costs of those ink jets that are worth nothing. On a small scale this doesn't matter, but on a large scale, we would have to pay disposal fees.
So money would have to roll from buyer to us, then minus costs to the charity.
Also, if we are actually registered then we can issue the tax receipts ourselves, and our basic software system is 90 % of the way towards being able to track that anyway.
Fortunately that's a problem we don't have to worry about yet.