Couldn't you just clean XYZ wallets by sending yourself dummy transactions between legit ones (or having the client automate it)?  Anonymint talked about this I believe.  The more you send yourself the better.  Also wasn't there talk of having some sort of injection nodes churning out constant dummy transactions?

Wow! This is great. About 400+ pages ago I talked about having a different kind of pool for change outputs only. Put in all of your change outputs and you'll get new flesh clean inputs of 10DRK. The client could automatically do this after each darksend, which would also get you new inputs for the next round.