An ultrasonic cleaner is the best method that I have found to clean records. There is no need to spend a lot of money on an ultrasonic cleaner. It is a very mature technology and the first patent for ultrasonic cleaning of records was issued in 1968. I built my first ultrasonic record cleaner in 1979 and used it for over 30 years with excellent results. There are a number of ultrasonic record cleaners available on Amazon for around $200. I personally have not used them but I know of several people who have and are pleased with the results. Just make sure you get a spindle that can handle multiple records and has adjustable speeds.
The key to optimum cleaning in an ultrasonic bath is using only distilled water and a suitable surfactant at the appropriate concentration, at or above the Critical Micelle Concentration (CMC). Non-ionic Surfactants are the only type of surfactant that should be used for cleaning records. Triton X-100, which was developed by Dow many years ago, is an example of a non-ionic Octylphenol Ethoxylate surfactant. In its day it was a reasonable choice for use in an ultrasonic bath to clean vinyl records. Today, the best surfactants for cleaning vinyl records in an ultrasonic bath are Dow’s Tergitol 15-S series of non-ionic surfactants which are secondary alcohol ethoxylates. Dow’s Tergitol 15-S series of non-ionic surfactants provide improved cleaning action with enhanced detergency and wetting, are highly soluble in water and are more environmentally friendly.
I would recommend Tergitol 15-S-7 as my first choice. The Library of Congress recommended recipe for a record cleaning solution consists of 2 mL of Dow Tergitol 15-S-7 in 4 L of deionized water (about 10 drops per liter). Another reasonable choice is Tergikleen which is a blend of two nonionic surfactants – Dow Tergitol 15-S-3 and Dow Tergitol 15-S-9.
The other keys to optimum cleaning in an ultrasonic bath are the rotation speed and time in the bath. The slower rotation speeds are more efficient at cleaning compared to faster speeds. I found that between 1 to 3 RPM was ideal. I also found that longer than a few minutes in the ultrasonic bath had little beneficial effect on the overall cleaning process and the possibility of a detrimental effect. I settled on a 6 min time for my records purchased new which had no obvious contamination and a 9 min time for previously used records. I followed the ultrasonic cleaning with a 1 min medium spin rate rinse in a second bath and followed that with a spin dry at a faster speed for a couple of minutes. This left no water droplets on the record surface but an occasional droplet on the record edge which I removed with a clean room wipe. I typically did 10 records at a time and the entire process took between 15 to 20 min.