So I ended up with a free ms310 with a scored piston, and a crank bearing that came apart. I tried cleaning the cylinder.. didn’t have any acid but lots of sandpaper. Had to go down as far as 100 grit to remove the aluminum. It’s pretty clean now but I don’t know if it’s still useable. If it’s not, no big deal as I only have my time and a few beers into it. The first pic is what it looked like once I tore it down.