mmmm... oil eh? its been a while since i last made some but i can describe the method i used,its safe as long as you are carefull ,you will need an electric cooker(don,t try this with a gas cooker,as open flames and alchohol dont mix)a clean tin can and a cooking pot/pan. put a couple of inches of water into the pot and gently bring it up to the point just before it begins to boil,you only want it to be at the point where tiny bubbles are begining to form on the bottom of the pot/pan, so were talking gentle heat here, next put your alchohol/oil solution into the clean tin can, dont fill it right to the top as you are about to place the tin can into your almost boiling water, once the tin can is in the pot of water the alchohol will heat up and start to boil and evaporate,controlling the water temperature is key here so that the alchohol does not boil too violently and overspill from the can, so be ready to turn the heat up and down as needed, if your doing it right the alchohol should be bubbling and frothing away while the water in the pan should be quite still due to the lower boiling point of the alchohol, it should take about an hour to boil off about 300 to 400 mls of alchohol, for safety only do this in a well ventilated area, dont leave it to boil unattended. once you are happy youve got rid of 99 percent of the alchohol(the bubbling in the tin can slows right down) just place the can somewhere warm for a couple of hours to get rid of the last of it and your good to go,no decrease in potencey