Solvent for parts cleaning tank

[wasfast]

I'm thinking about getting one of the 3 1/2 gallon parts cleaning tank with recirculating fluid (a whopping $30 on ebay new). I'm interested in what the shops or others use in their tanks. Also, is there some recommended filter method for the grit to remove it at the pump?

[rePhil]

I use mineral spirits in mine, no filter. Safety clean solvent works well too, not sure where to source it though.
Not sure what kind of filter you might be able to fabricate.
My routine has been to wipe off the worst with a rag followed by the tank. Then if necessary I will use Brake Clean (mostly on chains).
Saying that lately I mostly use smaller containers for chains. I have even tried putting the bottle on the washing machine to try to get an ultrasonic effect. Next stop will be an ultrasonic cleaner.