I'm getting close to final assembly for my engine. Oil pump (NOS OEM for $85!) is in, all new lower bearings, etc.

I found the oil galley plug on the front of the engine has mangled threads. I think it's a 1/2" NPT pipe plug. It is tapered and the Metric size (13.5mm x1.25)
didn't seem like it exists.

But my main question is on the surfaces for installing the head gasket. Both block and head have been machined, and I have a composite Ajusa head gasket and new head bolts. I've had issues with flash rust on the crankshaft and even some parts I've been cleaning in the space of a few seconds. The block surface is perfect, and I have had the piston bores well oiled as well as the surface where the head gasket will sit.

Normally, I get sealing surfaces clean, then spray/wipe them down with a powerful solvent. I'm worried that I will get flash rust if I do this on the block. On the other hand, I don't want to sabotage a new head gasket by leaving oil where it shouldn't be. Can someone weigh in on this? It might be a week between sealing the engine up and putting it in, especially if we get snow.

Cheers and happy almost christmas/solstice everyone.
I hope you're all doing ok in these hard times.