Sterilize 12+ jars (boil jars and lids for 10 minutes). Put them on a towel on the counter with lids next to them.
Put the vinegar, water and salt into a Pyrex measuring cup, place in a pan of hot water, and heat it to boiling point (double boiler method).
Clean the Brussels sprouts, and slice them in half.
Put the Brussels sprouts in the jars, add 1 chili pepper, 1-2 cloves of garlic, a pinch of cumin and coriander seeds per jar.
Pour the vinegar mixture over the Brussels sprouts to 1/4" from the top of the jar.
Wipe the lids of the jar clean with a sterile towel, put the lids on finger tight. With tongs, put the jars into a pot of boiling water, make sure the water covers the jar lids by at least 1/2" of water. Make sure the jars aren't packed too tight into the boiling water. Boil jars for at least 12 minutes, pull out with tongs, and put on towells on counter. Tighten the lids on the jars as you pull them out.