So I changed my stock tire tubes on my 26'' MTB for gel sealant tubes. The original tubes had not been punctured, so they are still usable. I pressed the little thingy on the valve to let the air out. A lot of air went out, but it didn't get to the point where it is foldable like when you buy it at the store in a little box. This prevents me from putting the tube in my wedgie bag for use as a spare tube. I can't find a way to get the rest of the air out. I've tried squeezing the tube while pressing the valve but no luck.
Is there something I can do or am I out of luck ?