I had 2 original "Metal Matches" with the orange plastic end. One I used to make fires and light camp stoves, the other I kept as it was received. I left the used one in a drawer for several years and all that was left was grey dust and an orange piece of plastic. The second one, I put a heavy coat of clear laquer on, it is still intact after 30 years. I have never used it.
On my Firesteel I keep a piece of heat shrink tubing. Any strikes and I recoat it with clear laquer and put it back in the tube. As soon as feasible. It takes quite awhile before they corrode to dust.