What if your Costco spiral ham did not have cooking instructions you know it is precooked but how long do you heat it up and when do you put the glaze on?

If your Costco spiral ham is precooked, you should heat it in the oven at 325°F for about 10-15 minutes per pound. For a typical spiral ham, this usually means around 1.5 to 2 hours. Apply the glaze during the last 20-30 minutes of heating to allow it to caramelize without burning. Always ensure the internal temperature reaches 140°F before serving.