What is T.S.P.?

Trisodium phosphate. Removes paint, don't know about your issues.

Editor's Note: It's recommended for washing walls before painting. It is caustic. It is usually available at hardware stores in the paint department.

TSP will clean mildew, dirt, etc. from both exterior & interior walls. Make sure you wear rubber gloves and ensure to wash the walls or whatever after.

trisodium phosphate can be found at paint stores, in the paint section at wal-mart and hardware stores. i used it to clean the aluminum siding on a house so we could paint. if your paint is old or if the siding was only given a light coat of paint at the factory it could remove the paint which is what you want if you are going to paint it but not if you just want to clean it.

TSP is also used for cleaning soot and grime off of fireplace brick ( very heavy duty cleaner )