Yeah.. for about 18 months I was buying all kinds of old Peavey combos.. and you can believe that some of them had some pretty cruddy, un-loved, tolex on them. Solution? Be prepared to invest some hours into this minor project.. so "patience" is the first thing on your "Restore This" list that you should be working with..
1. Patience
2. Terrycloth (size is irrelevant)
3. Hard toothbrush
4. "Fox tail" broom
5. Cirtrus cleaner
6. Small bucket warm water
7. 409 cleaner
8. "ArmorAll"
Take it apart.. as far as you are able to. Wet the terrycloth and do an initial tolex wipe down.. maybe a through vacuuming inside/out wouldn't hurt as a start.. get that 'foxtail' involved, pulling out any dust bunnies in the corners. Spray down the entire tolex well with the citrus cleaner.. let it soak in good.. 2 minutes later, hit again with the same stuff and this time add a coating of '409' and now start scrubbing hard with the now-wet cloth. Rinse & repeat this procedure at least twice. Use that toothbrush when you spot stubborn areas where the terrycloth isn't persausive enough, plus give it another good soak of the cirtrus spray. Now.. after you have gotten all the ingrained grime out of the tolex, you're gonna notice even thou its alot cleaner, it looks kinda 'washed-out' and old looking. Not to worry.. thats exactly what ArmorAll was invented for.. to restore man-made surfaces like tolex. Apply it liberally and rub it all in by HAND. not a cloth. Let it sit a good 3 minutes before wiping it off with a clean cloth or a "shop towel" you can find in automotive stores. If still not to your liking, reapply the ArmorAll a 2nd time. Now you are probably gonna notice that the chrome parts are kinda shabby-looking against that nice, clean, shiny tolex. Sometimes chrome can be restored, sometimes you'll have to replace corroded parts to finish the job completely.