Oil& air
Hello mate
just to reiterate what mark said ,A mineral based oil will self combust if exposed to pure oxygen, now air being only 20-22% oxygen the likely hood of it combusting is minimal,any fully synthetic oil is ok such as fully synthetic oil for your car engine 5/30w is about the thinest viscosity but ideally angel love juice is perfect give dan a ring at WDP or better still buy yourself a new Fill Nipple from any reputable paintball store for about £5.00 hope this helps
Darren Psycho pimps
Ps Mark ,whats happening about Skyball ??.send me a text when I can ring you.