I think Louisana Jeeper is referring to Klean-Strip Prep-All. I use it but the ingredients are not identical to Prepsol according to a MSDS for Prepsol that's posted somewhere here.
Du Pont is the maker of Prepsol and should be available from a good Paint and Body Supply store that carries Dupont refinishing products.
I've used Prep-All for initial wax and sealant removal assuming it may cut through them faster. Need to hold a cloth to the finish to make sure the product stays in place allowing the chemical action to do it's things, otherwise it just runs off the paint ( same fro IPA).
I use the IPA mix inbetween polishing steps, again allowing the product some time dwell by holding a cloth dampened with it against the paint.