Is it safe to use a USB charger for charging an 900mAh eGo battery? I don't want to fry my computer, but after seeing past posts on the subject, it seems that I can find opinions both ways. Guess I'm looking for more expert thoughts from some eGo vets on whether it really IS safe, or if I should just go out and buy a wall charger and be done with it. Also, does anyone know if madvapes carries 510 cartos with white filler for eGos? It's so messy and hard to use syringes (can't use my hands any more), but dripping is ok with all of my 808 cartos. Thanks.