Bulette

Sealant in tubes works well, in my experience. First try was with the kind of frustrating slow leak that could easily survive a ride, but the tire would be flat overnight -- not confidence inspiring. Add some Orange Seal, aired back up and spun the wheel: no more leak.

Definitely seals smaller punctures without a problem. When I eventually removed the tube, there were multiple points where the tube was lightly glued to the tire...

Fredo76

I use Slime for butyl tubes and Stan's for latex tubes. Haven't tried any others. Both work pretty well for me around here, where the main threats are goatheads. With my heavier hybrid bike with 38mm tires, I would sometimes find flats in the morning. Check for a thorn, give it a spin, pump it up and go. I eventually added more sealant when it happened two mornings in a row. Problem solved. When I finally changed the tire, the tube had maybe a dozen obvious places where the sealant had worked.

Sealant also has worked for me while on the road. Find the culprit, take it out, put the spot where it was on the bottom if necessary so the sealant can run down to it. Add some air, and if sealant leaks out, put your finger on it for a bit, then add more air when it no longer leaks. Then ride away.

HelpSingularity 

BITD I used slime in butyl tubes in goathead thorn areas like Bakersfield, Ca. What a lifesaver. Would do it again in a heartbeat. Except now there are a lot more choices for sealants.