1. Try and keep them upright at all times. When not in use, remove them from the battery and put the protective nipples back on to prevent leaking.

2. Don't inhale super hard. This just pulls material up faster than it can be vaporized and will clog the stem when it hardens.

3. If it's glass, you can just use a lighter to melt the material in the stem back down to the heating coils. If it's plastic, a low powered heat gun or hair dryer should work (just don't melt the plastic).

4. Some brands/styles of 510 threaded cartridges just suck. If you notice it consistently with a certain brand or design of cart, just stop getting those.

5. Make sure the voltage of your battery is appropriate for the resistsnce of the material. There is no consistency with the consistency of concentrates, at least for weed. You really only need to be between 3.4 and 3.7 volts. If your battery shows the ohms, that helps dial the right voltage in.

I do all this and rarely, if ever, have an issue with clogging.

Sometimes I'll poke a toothpick down to clear the blockage if it's really bad.

Storage is important. Try to store your carts upright. Breath control, over pulling will cause you to suck more concentrate than what is being vaporized. This becomes a clog. Light breaths are better and will make your carts go longer. Pay attention to the brands. I've almost made a spreadsheet to track mine, but have found a couple of brands that don't usually clog.