OK, I tried the furniture polish first as it was to hand and worked a treat! They're passable now. Have a few scratches on from me scrubbing but I suppose you have to look more closely to see!! Thank you for all your help and preventing me doing any further damage!
I had a drawing taped to a window for ages, and when I took it down, it left sticky stuff on the glass. I tried WD40, 2 different kinds of proper "sticky stuff'' remover, baby wipes, white spirit and also neat washing up liquid. The only thing that shifted it was nail varnish remover. Yay! But not sure if that would have been a good idea on your canisters if they are plastic? But glad the furniture polish helped.
I'm not sure what they are tbh, they're like tin / steel? It was the paint on them which was coming away the more I scrubbed so I'd assume nail varnish remover would have done the same thing. However, your tip has come in very handy as the back window of my car still has sticky tape on from when it was advertised despite many attempts to remove it!! So, I can now get to work on that too!!