Don't have to scrape anything. You loosen the screw all the way; it's captive so it doesn't come out of the block though. Then just keep wiggling the whole block until you can pull it loose from all that tar crap holding it together.
From there, it sounds like you're trying to disconnect the front lights harness from that block as well, so you can feed it through the rotten core support for replacement. That's a little tricky, too. You'll see there are 4 harnesses brought together in that block. The front light harness and the one next to it can be pushed forward as a unit, through the clip that holds the block together. Then in between those two, there's a pair of tabs that you can carefully depress to unlock the two harnesses from each other. The tar goo is in your way but if you pick carefully you'll see what I mean.
Richard