ok i have recently bought an a1200 of from ripoffbay
and it was really dirty like someone puked on it
first and easy steps where dismantling the the machine
i putted the 2 pieces and the trapdoor in the dishwasher on 55 celsius and on intensive cleaning
i know from experience that u must NOT put it on 75 celsius
i putted a c64 in it last week and it was wobling all over and could throw it away...pfew glad i have a spare
i also dismantled the keyboard and putted it in the dishwasher...it came out as new

only hard job is putting all the tiny little screws back on