Sulphur (or sulfur if you are from the colonies) is an element and cannot be "made" (well not without some tame supernova). If you want to get rid of fleas, remember that they need a host. Dog, cat, human, hedgehog, squirrel... If all of those have flea control measures in place then fleas will fail to survive. If your problem is not really fleas, but other biting insects, then you need local insecticides. Sulphur will be MUCH harder to use.
