The MSR stove gasoline canister pump dismantled, Special Note: the small white filter pad is NOT in any of the repair kits, and since there is nothing to prevent dirt from reaching it or moisture, Be aware it is easy to tear, I did so in cleaning off the dirt and moisture. Still usable but, I decided that extra protection was needed and added my own piece of screen printing mesh, about a 180+ fine screen to the outside on the pump button itself.
I have were fine sand where I put my stove outside to cook, and yes, like going to deserts or high mountains the dust is on everything.
I solve a part of the problem this way, and nothing is permanent, all replace-able and cleaning is easy.
A simple hair tie to keep it on, easy to remove to clean, lets air in, but keeps sand out. And as a screen printing mesh, yes ever the gasoline or kerosene will take a long time to do any damage… I used a lot harsher chemicals in those 1990 printing years on these screen meshes without worry