From the Amazon Deals thread:
https://www.ar15.com/forums/general/Amazon-clearance-deals-Team-member-edition/75-1697216/&page=909these things are basically $3 (or were, still cheap), delivered:
I'm tempted to run this in my wet-tumbler at maybe 20% strength. In particular, I don't ever dry tumble, and sometimes will run a couple drops of turtle wax, to leave a thin film in lieu of the dry-tumble dust film. My only real item of concern is if this has any amine's or other brass-harming additives. I can't tell. The warning only says "contains surfactants", which are just soap, so not worried about that (soap is in general organic in nature, and not really an amine - necessarily).
FWIW, I did Google RainX general composition. It's a filming layer, formed from this molecular back-bone
No amino groups there. I suppose I've answered my question probably. Just curious if anyone else has looked or tried this?