Hey Doug! Glad to see ya made it on... It took me 3 or 4 refills... but I do find that burning. I also notice that when refilling (I use a syringe after opening the cartomizer) the excess spill off juice is DARK brown (burnt!!!).
I wouldn't think it would be bad to use them.. just to refill them. I am allergic to PG so unless someone starts filling them with VG they are now useless to me Sad cause these DPV9's have such a great hit!
Spikey...Exactly when you see the burnt juice you can bet good money that the cart material will start burning up. As far as not refilling them at all.... I would have to go through at least four carts a day...It might be worth it since it is a pretty hassle free device.