Question: how to heat a fully cooked 10 pound ham?
Answer: If you're starting with a fully cooked city ham, bake it in a 350 degree F oven for about 10 minutes per pound. ... 
To help keep your ham moist and juicy, place the ham cut-side down in a baking pan and tent it with foil.
Every 20 minutes or so, brush the ham with glaze and baste it with the pan juices.