Mix it around 1:3 in petrol, or 1: 8 in diesel and use it in road vehicles. Will stretch the budget for a while!
No, don't put any of it through an engine with a catalytic convertor. The lead salts will quickly coat the "cat" matrix and ruin it for good.
But for engines without one, if you mix 1 gallon of AVGAS with four gallons of unleaded, you'll have something similar to old fashioned "4 star" petrol. Works well in old engines but you'll see a grey coating inside the exhaust tail pipe, just like in the old days of leaded petrol.