Originally Posted by Hodakaguy
I use a Harbor Freight Ultrasonic cleaner filled with Simple Green. You have to run it through quite a few cycles over a day or so but the valves will eventually come out looking like new with no need to scrub them with anything. You can get the cleaner on sale quite often, look for their coupons online.
I'll have to check that out, there's an HF store not far from me. Thanks