Usually considered a bad idea. Bacteria turns minor chaffing into nasty saddle sores. The only thing that I can think of that might help, and I'm not recommending this as a substitute for laundering, is to use a chamois cream that has antibacterial agents in it; maybe hops or tea tree extracts.
I use a little bit of this stuff mixed in with my chamois cream-
http://www.amazon.com/Tea-Tree-Cooli...431258&sr=8-22
A little goes a long way though.