To Rlawry's point: I pre-clean virtually every record that goes into the ultrasonic, to reduce the amount of contaminants that pollute the bath. There's no 'one way', but using a conventional vacuum record cleaning machine with appropriate fluids, followed by a pure water rinse, is a predicate to the next step of cleaning in the ultrasonic. I buy a lot of old records, and even with pre-cleaning, change the ultrasonic water out at roughly 50 cleanings.