Tumbling Pewter

Hello there, i would like to know whats the best soap/conditioner
to work with pewter Im using rotary tumblers and the company i used to
buy the steel shot conditioner form is now out of business… i’ve
seen a lot of products out theere, tried a few… they didnt work at
all !! they do clean the steel shot, not the items, they wont shine.

do you guys know of any good steel shot conditioner (i guess its
called that) so i can work with pewter ??