I assume the beaker was used because of the volatility of the cleaning solution, 99.9% IPA, perhaps. The problem with IPA is that it absorbs water from the air so quickly that it quickly becomes diluted and will leave a scum on surfaces. Acetone is very risky to use in large, open quantities but that's what I find works best for cleaning platters. When Acetone is used on a swab, I usually end up with curled-up heads, so I can imagine what 30 seconds in an UC would do to them. Do you know what he used, Jared?