What is TSP? Some kind of cleaner. Never heard of these abbreviations.
She is referring to the cleaning agent TSP.
It stands for trisodium phosphate. Heres a link to it! https://www.homedepot.com/p/SAVOGRAN-1-lb-Box-TSP-Heavy-Duty-Cleaner-10621/202935861
Its a strong cleaner, I use it before painting furniture.
I use it to wash walls, or anything for that matter, before painting.
a cleaner used to prep for painting by deglossing the surface.