what is the physical difference between streight veg oil and wasted (used) veg oil? Does heating it up change the way it will burn? Help me out please.

 

No real difference that I can tell, except the SVO (unused veggie oil) smells faintly of popcorn, and the WVO I get smells like a smokey chinese food dinner. I got a barrel of oil a month from a Chick-fil-a for a while, and that stuff smelled great.

They only physical difference I can imagine is the particulates and water suspended in the oil needs to be filtered or settled out.