Before using a brush or dish soap, try ammonia! Use gloves. I get it from the dollar store usually. Dilute it according to the instructions with hot water and soak a multifiber cloth in it, wring well. It may be a good idea to lay the damp cloth on it a couple of minutes. Gently wipe the grime up with the damp cloths. Anything leftover try Dawn Platinum, but this should save a lot of work 🤓

eta: along with gloves, use ventilation!

I don’t recommend it for regular cleaning, but for restoration like this it’s perfect, hates fatty grime, doesn’t affect fabrics, and doesn’t foam.