It happens that Scott formulated :
In the old days we used to keep opened tins in the fridge. I think
you could even buy a plastic lid to fit on the tin. Now we are told
to transfer the contents to another container.

I/we don't bother, we put the opened tin in the fridge, but covered
with one of those plastic tops that comes from those crisps in a tube
(name?).

Some tins are plastic lined, which prevents the contents attacking the
metal lining. I take care to ensure what ever the lining, that the
lining has not been discoloured whilst stored in the fridge -
pineapples seem worst for this. We limit to storing no longer than
three days.