Said before but there is a product called Rust Check. It is available in the USA. You simply take it to them, no cleaning required, they spray it on EVERYWHERE. Your vehicle is dripping when you come to pick it up. They even drill plugs on the rocker panels and impossible to get to spots like doors etc. The spray fires it in there with all holes plugged. Then it is a once a year maintenance which is way less money than the first install. It works and does get into the internal chassis sections. Good Luck