I'm still fairly new to the pellet burning seen but about three weeks ago I started a ton of Maines Choice.I want to start by saying although they have a little more ash than average,the heat that they are putting out more than makes up for it but when I run the shop-vac to suck up excess ash during weekly light cleanings Ive noticed a light petroleum odor.The smell is very light and it does not concern me(it kinda smells like my clothes after a long day of snowmobiling)I'm just woundering if anyone else has noticed this.They are a good pellet and I would buy them again,I'm just curious!