Please edit this thread ASAP in view of what Noman just said. DO NOT EVER heat naphtha like you mentioned, for a warm water bath you FIRST boil the water, turn off the fire/heat source, and THEN submerge the open container with naphtha in the warm/hot water.
Also DO NOT add lye to the container and close tightly and shake, thats a very bad idea, the heat generated creates pressure that can make the glass explode and make some real real serious damage.
Also you make no mention of safety equipment (Goggles, gloves).
Thanks for trying to help others, btw, but please take care of yourself and others and edit this tek!
Once you edit the safety issues, you can delete the moderator warning im adding at the beginning of your first post.