You could try using some kind of anti-bacterial spray without any harsh chemicals etc. Something herbal/natural would be good if you can find it. Give it a really good wipe down and then go over it with water and a cloth and make sure you get rid of it all REALLY thoroughly to prevent poisoning of the fish. I've heard lemon juice can work really well (practical fishkeeping), especially if you have any limescale build up on the tank. Just make sure to get that off really well, as it could alter the pH.
Thank's for your reply
I was thinking of dettol, the dettol surface cleanser? that you use for kitchen work tops and and food surfaces ect, as on the bottle it says none bleach, no taint or odour. Would this do the job? and I was told a few years ago about lemon juice, as this is what i use for my microwave