Is it necessary to use bar & chain oil for chainsaw lubrication? I found a few free quarts at the hazardous waste facility, and have been using them, but am running out because my electric chainsaw leaks pretty bad (I've already tried to find the leak, but where the line goes, I'd have to remove two screws that holds the engine, and I stripped them). On the last quart, it says it's 30 weight oil. Can I just use straight 30 weight motor oil instead, or does the bar & chain oil have some special properties? Up here, there's a small container of 3-in-one oil in the shed that's 20 weight, and yesterday, I squirted a few drops of it into the chain groove every few minutes, so far without problems.