The Alpha series OS four stroke engines have plated cranks, cams, and rings. There should be little left to corrode. I like to run the engine WOT for a bit to get things hot, cut it to a high idle for a while to let the oil system do it's job of venting the crankcase and cut off the fuel to run it dry. This is with an FS-52 I added the oiling system to. I've been running home brew methanol or E85 with Klotz Original Techniplate. I got a used FSa-81 second hand that smelled of fuel when I pooped the backplate off, but the bearings and parts where clean.