My Amiga 500 1.2 has been treated like a nightmare since 1988, when I bought it. The eject spring failed after 5-6 years and I kept ejecting the disks pressing the failed button to lift the disk and using a pencil to take them out.
I brought it around my friends' houses, and even abroad. It's been below zero more than one time (here it's impossibile to keep mobile things frost-free - something always happen sooner or later ;P like the warming failing or carrying it from a house to another.
It's yellow, but it still WORKS like a dream even today, when I use it to play games that don't work on my A4000.
The secret is probably to never really take it away. Don't spill anything on it, and clean the innards with a small vacuum once in a while to remore ash, dust, hair, skin scabs and so on. Avoid power failures while on, and play it once in a while and I'm sure it won't die for a long time.
Haakon, for the yellow-ish things... you can use wood polish spray and a soft cotton tissue. I use it and it's nearly white. Ok not white like when I bought it - that kind of yellowing can't be avoided - but the stark yellow can be cleaned a bit.