This all started with a fuel tank. I drained the summer fuel out of the tank and the color was a rusty color. I decided to remove the fuel tank and clean it out. A week of soaking in vinegar while i ordered the por 15 fuel tank liner. Then i put a chain in the tank and shook it alot. Dump the vinegar and chain out. Rinse out with paint thinner 4 times and what a nasty color came out. I then used some muriatic acid for a last cleaning. Dump acid and rinse with paint thinner. Pour in the por 15 and swish it around let drain and dry. One week later did the por 15 once again and let dry.