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I bought some 28-second quenching oil from McMaster-Carr a while ago and I accidentally set it on fire today so I'm guessing it wont be too good for future quenching. I suppose it's not a big loss since I'm pretty sure I want a faster quenching oil for my 1084 anyway, but my question is how do I dispose of it? And once I do empty the container do I need to wash it out before filling it with canola oil? I'm still pretty new to this stuff so any advice is greatly appreciated.

Solomon, your oil may or may not be toast depending on how long and hard it burned, doe some test quenches with it and see how it hardens things. When mine is worn out I use it for lighting fires, just a little bit on some wood or paper in the ducks nest will help a coal fire get going. I have a large container of old oil in my shop that I use for other cooling operations not as critical as the final quench but mostly I use it to refresh my fire starting tool. My fire starting tool is a ball of ceramic wool held on the end of a steel handle with a wire mesh. This ball is soaked in the old oil and when lit can be used to safely light my gas forges without getting my hand near the opening. I am also a firefighter and it is very handy when my Dept. does a controlled field burn, I just light it and walk along touching it to the dead grass and in no time can have a fine line 200 feet long.

If none of these ideas suit you I am sure you could drop off the oil at any oil recycling site, be it ruined motor oil or quenching oil it is still a petroleum based oil that can be reprocessed.

I believe most AutoZones will take used oil also. I have dumped off some very nasty motor oil there in the past. I don't think it would matter what type of oil it was.