Proper black tea isn’t hard to come by here in Prague, but it is pricey. I’ve become a bit creative at salvaging what has gone cold in the mug or the pot. We don’t have a microwave, which would seem to be a logical solution, but then again, microwaved tea always tastes funny to me.
For me, the easiest way to warm something liquid back up to drinking temperature is to add in some boiling water. Not too much mind you, because you can dilute it too much to be palatable. However, a tablespoon or two of boiling water to a mug of cold tea should warm it up to a nice temperature without affecting the flavor. The alternative is to add very hot milk, if it’s a latte, milky tea, or something similar.
Of course, a cleverer person would either drink their drink before it got cold or keep in an insulated cup of some kind, but that doesn’t always fit into my life, so I have to resort to other, less elegant solutions = ).