The CRC stuff in the can is designed to be sprayed in the intake while you rev the motor. The fear many have posted about doing this is if you have a lot of buildup, you could knock a chunk of built up carbon loose that hasn't had time to dissolve. This chunk will then be passed into the cylinder (not good) and later possibly pushed through your turbo impeller and well, you know how those things go. According to the company, this is perfectly safe to use on our trucks, but YMMV. They claim it will "Dissolve" not dislodge. After using it, I must say it does dissolve carbon well, however I used it in a non-conventional, not advertised manner.How does it work ?