Can I get an Amen..... :
I had pretty good luck with these air cleaners...They'll usually light up if you let them go too long without changing or cleaning the foam filter,due to fuel and dust residue in the foam filter--Every now and again if I didn't change the filter,--I would take the foam filter out and dunk it in a bucket of water ----you can add some mr clean or similar grease cutter if you want , squeeze out the excess water and put the filter back .--It seemed to work....