OK, several posters have been recommending them. I finally got mine out. Its the 2.5L model from Harbor Freight. Got it on sale for about $69.
I've been using it to clean up one of the three 1975 Nishiki Internationals I picked up Sunday. The bikes were in decent shape, but had been neglected for decades.
I would definitely recommend you not get one any smaller than this unit. I had the RD and one brake caliper, and that just about filled it up. The bath is about 10 to 20% "Awesome", the rest water. Picked up the Awesome at the local Dollar General.
Here is the RD after treatment. You really can't tell, but all the gunk on the pulleys is gone, along with the dirt and accumulated crud. I also used it on the bottom bracket. The cups shine like new.
I'm planning to have some fun with these Internationals. Three 1975s, all picked up at the same time, and two are identical.
The fork on this bike is sitting in oxalic right now. It is not too bad, but it has light rust on the chrome tips and fork crown.