Please do not quote me here!
I would NOT run any solvent thru the accusump. I think there are o-rings inside that may become damaged. Flush with thin oil, maybe 10wt. this will require some pressure. There is a piston inside the tube that will be all the way to the end where the inlet hole is. This meens there should not be very much contamination inside. If the air on the back side of the piston has been let out the piston might be short of the open end? The oil lines can be flushed with gas or any type of solvent. The oil cooler can be flushed with gas or solvent also. Be sure to then flush the solvent with clean oil befor intalling in your car. You might want to then start the motor run just a few miniutes, drain the accusump and change your motor oil. Oil is cheep, repeat oil flush.
FYI, Whith the accusump empty you should add 55 lbs of air, then bleed down to 7 psi on the back side of the sump. There should be a pressure guage mounted.
Good luck,
Dan