Hello,
The fridge in the flat we were living in got all discoloured on the white plastic- some browny and dark grey stains. Was weird as not from food residue or anything and we cleaned the fridge including trying bleach but nothing shifted these weird stains. Have no idea why the fridge discoloured in that way. In the end we just left them but now our letting agent has gone mad about the state of the fridge so am asking the wisdom of mumsnet to help incase there is anything we can do to rectify it without getting charged for a new fridge!