Cover it with a thick lid.
keep it in a hot place
No. Use Styrofoam.
warm it up every time it gets cold
No, a galss cup does not keep any drink warm long.
You can keep it warm by keeping it out in the sun. If there is no sun, than I don't know how it will it will stay warm.
Yes it will .
try covering the glass, so the heat particles stay inside the cup, and the hot water stays hot.
Not for very long... you'd be better off with a travel mug
Sit on it(incubate) /place int in hot water.
The moisture in the warm air collects on the cold glass. When enough moisture collects, it forms beads of water that run down the side of the glass.
It would make a warm inked water! (I think this may not be true)
It depends on the type of glass. If it is on a window, try using a hair dryer to soften the wax, then dry paper towels to wipe it away. When it is down to just a thin residue, continue with dish soap and water. If it is a glass item that can be submerged, put it in a sink full of hot water (not boiling or hot enough to shatter it) and let it soak for a while. While it is still warm, wipe it away with paper towels. Replace the warm water and keep at it until it is gone. Wash it with soapy water to finish it.