What is the best way to warm up left over canned cat food? I don't think my cat likes it straight out of the fridge, and I'm not sure it's healthy for him.
I feed my kitten half a can of wet food at a time. The remaining half goes in the fridge until the next feeding time. I usually set the can out on the counter a little while before I intend to feed her, to let it warm up to room temperature. She seems to have no problem with this, although I have noticed that when I don't plan ahead and give her food straight from the fridge, she typically leaves most of it sitting there and comes back to it an hour or so later.
I've also warmed up cold food in the microwave, but be careful that it does not overheat! Depending on the type of food, microwaving may dry it out a little as well, so you might mix in a little water if that happens. And of course don't microwave it in the can :)
This question may be interesting to you as well: Does leaving wet pet food at room temperature for 12+ hours pose a risk for your cat?
Get a basin, like a mixing bowl (plastic if possible) and fill with water from the tap on full hot. In other words, turn your tap water to maximum hot and fill the basin with the hot water.
Put the cat food in a soup bowl.
Float the soup bowl in the hot water. It will be nice and warm in about 15 to 20 minutes, and will lose none of its moistness.