I definately cook off the residuals before using it. Tossing SS onto a hot burner and making it glow does the trick. I order my SS from a company in Oregon through Amazon. It is very clean but it is metal. This means that it was created on metal forming machines. ALL machines that cut metal, even fine brillo pad metal must do so with coolants and lubricants of some sort. The coolants used to cut metal in the machine tool manufacturer that I have known are generally benign to humans. The most notable health risk to humans from these lubricants and coolants has to do with the fact that there are micro organisms (biomass) that thrive on these things. So the coolants become contaminated with micro organisms. This is why coolant will stink the first thing in the morning - anerobic biomass breeds in the coolant when the machine is shut down overnight. With the machine shut down and the coolant no longer flowing the coolant becomes oxygen poor. Perfect conditions for anerobic bacteria which produce stink. They also can trigger dermatitus when they contact the skin on a chronic basis.
The oils otherwise are pretty safe around humans. Picture a typical welding shop - metals of all sorts are routinely heated to molten and beyond and routinely with the individuals face very close to the process (behind a welding mask with generally zero fresh air ventilation). If the oils were intrinsically toxic they could not be used in the production process.
I made a killer great vaporizer entirely out of stainless steel. This puppy can fill an entire room with a thick vapor cloud in a minute or two lolz. When I cooked the pipe and SS wool in an oven at 550F for a while there was indeed some residual oils that burned away from the pipe but to be fair I did not wash the pipe in solvent first. I also once vaped off some SS wool that had been used to clean my pancake pan. I immediately tasted the veg oil used and frankly it vaped pretty well. Yum! Gave me the screaming munchies!
