no matter how many blankets you wrap around a jar, the jar isnt going to warm, blankets would only keep the heat if it was already there in the first place (for example a person with its body heat, staying under the blanket). So no.
its very simple to warm naphtha, just boil some water, turn off the fire/heat source, put the naphtha in a glass and submerge the bottom of the glass on the warm water for a couple of minutes.
anyways you dont necessarily have to warm the naphtha, just make sure that you do more than 3 pulls (better more like 6 or so) and that the last pulls are long, with many cycles of mixing/letting stand before pulling out.