I've had some challenges with goat head thorns in my mountain bike tires. I got a 100-pk of Rema patches but quickly ran out of rubber cement, since i only had a couple tiny tubes from some patch kits. This Slime brand rubber cement works really well. Locate the hole(s) in your tubes by inflating and dunking in the pool or tub; I use a sharpie to mark an X or * at the hole, then sand the area to remove the surface rubber (which has mold release from the tube manufacturing process), DEFLATE THE TUBE, dab a button sized drop of glue and spread it around with your finger to make a THIN layer of glue covering an area larger than the patch, give it a minute to dry; then peel the metal backing off the patch and apply it over the hole, orange side down. Press and smooth it firmly, and leave the clear cellophane in place until the patch has set up for at least an hour.
This is a quality rubber cement for patching tubes and such. I use Slime Rubber Cement with bulk patches. I hate running out of patches and the glue that comes in patch kits is good the first time you use it but by the time you get to the second (or last) patch, that glue is unusable. I bought my first tube (which, by the way, I'm still on but it's getting low) in late 2012 which means that this tube has lasted a couple of years, opened, but tightly capped with the included cap.
This glue is thin, so it spreads nicely, and make for a good-quality patch. And, tightly capped, it lasts Recommended