Hey folks!
I'm new to the forum, but this is an area I specialize in (I have a mobile company that provides hydrojet cleaning of RV tanks). Honestly, the only way to get the sensors back working is to attack the debris -- and build-up -- on the them with high pressure water.
If you're interested in finding someone near you who can help, message me.
FYI, the Pine-Sol/Calgon solution is a great idea -- after you've got the sensors clean again.