I recall the laundry guide for a 1962 Whirlpool toploader detailed a procedure: Fill the washer with hot water and a good dose (up to 2 cups) of a non-precipitating water softener such as Calgon. Add clothes and agitate a few mins, then soak for a few hours up to overnight. The water may "thicken" from the released residue. Drain/spin the load, then wash with a good detergent.

STPP functions as a non-precipitating water softener.

Thanks, nice that they have that in the material that came with a washer. I didn't even think to see if they had that with my washer. [g].

I don't think Charlie's is supposed to leave any residue best I remember. Not sure that's true but was a selling point at one time.

Yes, that is one of their main selling points. They even recommend cleaning out your washer of detergent residue by running your washer with 2 scoops of Charlie's Soap and wash some rags before washing clothes with it.

I had read that too. Maybe I don't need to bother. Thanks.