1) Cut off a few mm of mouthpiece of Ecig.

2) Look for atomizor vent holes, use a very fine needle, or better yet a very fine piece of wire to clear out any residue in it.

3) Overnight 99% alcohol bath.

4) Try to excessively (Brute force) smoke thru the problem.

5) Recharge one battery for a minimum of 12 hours.

6) Add PG or VG to your juice.

7) Try a controlled burn - Inhale for an exceptionally long time non stop if device allows to burn off residues.

8) Clean out residue from mouthpiece.

9) Stick in a New Atomizor.

10) Blow "Out" hard instead of breath in to clean out some parts.