They have those warmers that you can use that have candles under them to keep them warm. Actually, they are like butane or something. You could get some of those and then put water in them, and put thermos s in those to keep them warm, or something larger. Best wishes to you and your business.
Why not go for a very small investment in your new business and put a propane tank and a couple of single burners on a small table? Each burner can hold a 12 quart kettle of water or larger. These can be found at a sports outlet. The burners are very inexpensive, also at the outlet. A thermos won t hold heated water indefinitely, you ll want to be able to control the end result.Len