I tried this for a while. I used a syringe and a big ass hypodermic needle (the kind they use for epidurals) and I would inject Stans into the tube....the Stans would seal up the hole just fine. But it was not worth the hassle......first, its actually pretty difficult to score a needle (you can't just buy it at Rite Aid). Second, you never knew how much sealant you had left in the tube. And the needles and/or syringe would always clog up, no matter how carefully I cleaned them...... also, i think Stans needs to be exposed to the air in order to dry and seal a puncture.....some of my punctures would not seal and I think it was because sealant would get trapped between the tube and the tire and would remain in a liquid state..