Spent a thankless day trying to clean my spare gearbox for the RS Turbo. Gunk, pressure washer, tooth brushes, magic eraser, wire brush.
Want to spray this with alumablast and given that's a bit pricey, don't want a cock up.
Still have the box in the car to do when I get the engine out and don't fancy repeating this fiasco.
How do folks go about it, steam cleaning, bead blasting??
Cheers

 

Seen gearboxes brought up to a really good condition by aquablasting, might be worth a look

 

Truck wash and a steam cleaner

 

had mine blasted and then used a cheaper alternative than alumablast has its a little too silver for my liking so used 151 metallic spray paint at 1 quid a tin looks more OE colour ,