In case you didn’t already know, VHS has purchased a ultrasonic cleaner.
I’d picked up some big bearings from North Star recycling.
These were dirty! As in caked with dirt and grease and they definitely did not spin.
First a round with acetone then sandblastong to get rid of the majority of the dirt and gunk. However this was not enough to get the grit/dirt out from inside the bearing races/cage.
So a few 15 minute heated 45 degree celsius cycles in the ultrasonic cleaner with just water and a few table spoons of dish detergent was enough to clean the rest. These bearings all spin very nicely now.
Oh a and quick blast with the air compressor to dry them out and slow down any rusting.
Check out the Tools Wiki for Instructions on how to use this amazing tool