I'm running mine through the ultrasonic cleaner right now. That'll sort any residual oil.Gees that's not good. Mine was clean...unless i'm to dumb to have noticed. I always worry about oil but never clean anything beforehand. I can only remember of once I tasted oil...ever.
I have been using a 2.5mm round wire coil in it so far....I only use round wire....i'm a simple man.
Been thinking of doing a 3.0mm one, but there's not much space in there....don't want to run the risk of smelting that airflow ring.
Anyway I made a 3.0mm flat wire and it fits nicely. Slapped on the original 810 drip tip to. Now it's exploding with flavor. I'm convinced 3.0mm coils make more flavor than 2.5mm.
I'm using 2.5 too but I did notice that on Mark Todd's video he used a 3mm. Might give it a try but my only 3mm drop ins are SS but I could always make one I suppose....lazy

. Seems they discount you on the product, but screw you on the shipping.
It's a completely basic bypass, no adjustable airflow, DL device. I love the centre fire button, the 5.5ml pod, the size and the quality. It came with the 0.25ohm coil, which I'm guessing is 50w at full power - and the flavour is fantastic. Airflow is perfect and it's also cloudy as hell 