Generally, you can stick the gallon of base in a sink with warm water, and that will warm it enough to add the fo. If she is only doing a container or two at a time, I wouldn't heat the whole gallon or so. I have cheated at times :embarasse And placed a bowl on my scale with a ziplock baggie in it, tare it, then add my amount of lotion for the container. Once it was weighed, I have tossed it in the micro for about 10 seconds or so, just enough to take the chill off, put it back on the scale and added color and fo. Get all the air out of the bag, seal it, cut the corner off, and you can easily pipe into your lotion bottle then. I *normally* make bigger batches of lotion and don't use this method, but if she is just testing, it would work. Don't get it too hot or you will kill a preservative, you just want to take the chill off. HTH I just realized that you said 1/2 - 1 oz fo, That must be for a whole gallon then, right?