I had Slime back up bad in the valve stem and then harden. The only way I was able to deflate the tube was to actually destroy it. I've switched most of my bikes over to Air-Loc now, it doesn't back up into the valves and it doesn't harden. It's the "next generation" Slime. Also, I was told by my LBS to make sure when I parked the bikes to have the valve stem up so the Slime couldn't collect in that area. Unfortunately, I don't think you can mix Slime and Air-Loc, but it might be something worth looking into next time you switch out tubes.

OH: on the road bike I run Air-Loc tubes And a teflon strip just to be safe. (kinda like a belt And suspenders!)


I forgot: my LBS suggested putting the tube in hot water to help loosen the Slime if it happened again.