Re: Will button's/coins deteriote when i dont peserve them?
For copper coins I would recommend a soak overnight in distilled water to remove any harmful minerals or chemicals from the ground.
I also advise some sort of preservation for pewter and iron relics. For pewter, vayank is right--some sort of clear acrylic like nail polish works. I prefer a 50/50 mix of elmer's glue and water, painted on with a paintbrush--or a thin coat of clear urethane painted on and thinned out with a small brush. Practice first on a relic that is not very valuable, for sure, and see which "finish" you like best.
For iron, electrolysis is the only way to go.
Other relics (brass or lead) and coins (copper, silver, nickel) will be just fine over the years.
-Buckles