Do t worry if he doesn't tell you the name of the chemical. Anything can be degreaser by soaking over night in soda bicarbonate ( washing soda) which has ph of 11.7 which is safe on aluminium whereas sodium hydroxide ( caustic soda has pH of 14 is dangerous for the user and aluminium. Please soak any greasy part in a hot water containing 100 GM's of washing soda in 7 to 20 litres of water after thoroughly wiping the sludge with cotton . Most important thing is water must be hot, carefully dip the items with out letting it fall on your skin apply Vaseline before you do the job and wear long thick industrial gloves and safety glasses for eye protection, next day remove the items discard the bath safely and thoroughly wash with hose before you scrub with a wire brush or wire dish wash scrubber, please use surf Excel soap softened by soaking in water it's the best way much better than surf Excel powder and liquid. This works on greasy sludge, caked carbon and stubborn baked carbon , you may have apply pressure while scrubbing stubborn baked carbon, you don't need to apply much pressure on caked carbon. Greasy sludge comes of when you wipe it leaving only a greasy film which easily comes off. I have been doing this for years
