[jeffahart]

I bet the firewall will clean up nice. Do one bite at a time. Take a spray bottle of 409 spray cleaner. Spray a 12"x12" area and wipe with a red shop rag. Do bits at a time. I bet some 409 will make that fire wall clean up nice. Clean the wires and everything. Can't tell you how many times I've made wire insulation look like new with 409!

409 is my go to cleaner. But I now use "Tub O Towels" to clean up my hand tools. Easier than spraying 409. From what I see you don't need a heavy degreasing, just some elbow grease.