This just in from the folks at the Magfire factory:

The coating is there for 2 reasons:

1. To prevent accidental ignition in extreme transport conditions:
In a gas / fuel filled container where you would have to crush pack to make
a spark, then again anything that has metal in it could make a spark.

2. Corrosion in extreme conditions: A very long period dipped in salt water
or similar. If you put Magfire in soil and let it be there over a year
without coating you'll notice a thin layer of rust over it, but it still
works 99%. So, there is no need to re-coat it for storing it unless you plan
to keep it under salt water for a long time.


I know the coating clogs the striker the first few times you use it, but after a few strikes, it's gone and out of your way. this is why I advise people to buy TWO magfires - one to practice with and one to pack in your PSK.