Clogged up nose when snorting

[AlienLinux]

Whenever swim snorts a drug that creates a large amount of powder or a medium amount, after awhile, one of his nostrils clogs up with some build-up. Is it the powder mixing with snot? Anyways, eventually it gets to the point where the powder can't get behind his nose, thus he isn't able to alternate between nostrils.
So swim has no choice but to use the other nostril the rest of the time.
Sometimes (specifically with a large amount of powder) the other nostril clogs up, and Swim has no choice but to just swallow the rest of the powder.
What is Swim doing wrong for this to happen? Is he even doing anything wrong?
Let him explain what he does so swiy can point out the problem more easily.
1. Swim crushes the pill into fine powder (no chunks at all).
2. Swim divides the powder into lines about this (--------------) long and maybe about a millimeter thin.
3. Swim sticks the [3 to 4 inch] straw or rolled up dollar bill in his nostril and touches the hole that leads to behind the nose.
4. Swim takes a deep breath.
5. Swim slowly and softly insufflates the powder in a straight line.
6. Swim quickly tips his head at about a 75-degree angle, puts his hand above his eyebrow on the side of the face where the nostril is, and breathes in quickly (while still holding the other nostril shut) maybe about 2-3 times.
7. Swim repeats steps 3-6 alternating between each nostril every line, until all the powder is used.
8. Swim goes and insufflate some water to clean out his nose a little bit.

The problem is, a lot of times Swim is unable to completely do step 7 because his nostrils clogging up.
Any help would be appreciated.