As you can see, aside from the literal dirt caked to this cylinder head, there is a decent sized carbon deposit on the gasket surface from the engine having been ran with a blown head gasket in the past. The lower gasket surface has the exact same marking. I was wondering a safe way to clean this without ruining the gasket surface or if I should even try removing it?

Hard to tell from the pic how bad the build up is. If its relatively thick you can use a scraper (carefully) to get the majority off the gasket surface. Then wet the area with something like Kroil or Hoppe's 9 to help dissolve the carbon, then wipe off. If you have a surface plate you can lightly lap the head gasket surface too.

Just don't go crazy on it. I cringe when I see someone cleaning gasket material from aluminum with an air grinder and roloc disc. Yikes! Just use the tool between your ears and you'll be fine.

I like Acetone on a wet rag.

Mr Muscle oven cleaner works a treat .
You could spray that on all that surface and it will get rid of 95% of the crap.
Don't get it on the nice bits,and don't breath it in or it will de carbonize you as well.