Hi
Parts washer:
We use a Zep parts washer (Dyna clean model, about $3k) and a harbor freight one (about $150). The Zep one is clearly better, and it gets the most use, but I can't say if it's worth the price difference.
The main difference we noticed was when we switched from mineral spirits to a biodegradable, non toxic degreaser. It's nice to not to have to worry as much about proper venting, long gloves, eye protection, etc. But, I'm sad to say that the healthier stuff does not degrease or clean nearly as well.
Regs:
We have an arrangement with a car detailer. For fear of scratching customer cars, they start with new rags and only use them once. So, they give the used ones to us by the garbage bagfuls. Since the rags are already recycled, we don't feel so bad about tossing out the ones we get the grungiest.
Hope this helps,
Greg
Long Island Bike Co-op