Just go fill up your car. That oughta wipe it out.
One caveat you do need to be careful using some of these directly at the pump (not a problem with the card itself), but some gas stations payment systems when used at the pump will seek to put a large hold (sometimes $75 or $100) on these types of cards and if there is not that much money on the card it can cause an issue. Again, that is not the fault of the card but just the way some gas stations authorize the card in advance. You may want to walk in (like you are paying in advance with cash).