Trisodium Phosphate (TSP)

Today, TSP is commonly sold as a heavy-duty cleaner for preparing surfaces before painting, as it cleans, degreases, and slightly etches surfaces to improve paint adhesion. It is also utilized as a food additive (pH regulator), a flux in copper soldering, and for cleaning masonry and concrete. Because of its high alkalinity, it can be caustic; it can damage grout, stain metal fixtures, and cause skin irritation, requiring protective gear during use. Many “TSP substitutes” are available that use sodium carbonate, which is less effective but more environmentally friendly.