I would spray it down with WD40 and with a single edge razor blade to cut off all the rust and crud from the blade. A wooden coffee stir stick and a paper towel will get the soap and gunk from between the scales.

Some 000 steel wool and some more WD40 will remove all the rust from the blade and metal polish will shine it some and leave the patina and etching completely intact. Same for the scales then polish them with a paper towel and metal polish.

You will end with a clean razor with a nice patina, and you can decide if you want to go further with the polished route or leave it as it is and hone it.

I do like a razor with character, looks like you may have one there.