In guessing you mean hull and toobs or just the tubes?
Either way. A powerfull jet washer to remove 20% or however good or bad it may be and international antifoul remover and a scraper. Either way its a foul job!
May need a couple of goes then finish off with white spirit and a scourer works well. This goes for the tubes as well.
A 5.5 meter hull takes a couple of days. Approx.. if the foul has been keyed in then could take longer. Copper coat antifoul may not come off completely
This way worked for me but there will be less labour intensive ways im sure