As a side note, and along those lines, bear in mind that TEL (tetraethyl lead) is very toxic. All the dreaded lead-based paints you hear about have nothing on TEL. When you clean your airplane, all those whitish deposits you see around the exhuast, and the white sludge that you find on the belly of the airplane behind the exhaust, is lead. Be really careful, especially after burning fuels that have higher TEL content (which includes 100LL, by the way) when cleaning the airplane. That stuff can be absorbed through the skin and can hurt you. Exposure is also cumulative. Something to keep in mind.