> Silver conducts beter than gold.
Now you know that is wrong.
Silver is a little better than copper. Why it is used in radio-frequency coils where most current crowds into the skin of the metal, so a thin layer of your very best metal makes a difference.
Though in most RF work, I always thought silver plating was more a fad than a benefit.
But who cares about conductivity when you are putting micro-inches of metal in a many-inch long path? You could iron-plate those contacts and never know the difference in conductivity.
Until it rusts. Silver's tarnish is a poor conductor. About the best thing you can say is that it will scrub-off easier than copper tarnish (or iron rust!). So when the contact fails, a quick out/in may restore it. That actually works in switches and relays which work by moving. But in a card connector I'm not sure what the point is. You have to stop the gig and jiggle the card. In another second you can scrub copper-oxide on your jeans and get it working again.
The gold-standard is of course GOLD. Conductivity is not great, but again we are talking a VERY small percent of the total path, so its "extra resistance" is negligible. And Gold won't rust. (That gold-colored stuff they use now for "Gold contacts" sure will.)
There is a guy who sells home electroplate, including gold. I think about $99 for gold (others less). It is a pen-light with a felt swab where the bulb was, and an aligator clip. You soak the swab in solution, put in a battery, clip the aligator clip to the object, and rub the swab on it. The electrons carry the gold onto the object. It isn't good for much more than a few gold fingers, but could be worth it if you have poor contacts in profitable gear. (But how do you gold-plate the inside of the other connector?)
I think Platinum will work if gold is too cheap or gaudy for your taste.
Interesting story. Silver is not only a better electrical conductor than Copper or Aluminum, it is a better thermal conductor. (The two properties are related, though stuff like ceramic foils the electrical conductivity.) Some guys making motorcycle engines figured a silver engine head would run cooler. Well, the price was a shocker: you end up with a bank-guard watching the job and searching everybody who leaves, and carefully saving every bit of dust for sell-back. And silver is so soft that when you bolt it down, it squishes. You alloy with copper to harden it, but they ended up more copper than silver, and thicker too. AND heavier! So it didn't run any better, and they didn't get back all they'd invested in silver bars.
> it smells like ass.
A lot of electroplating (that powder is electroplating, it sets up its own charge) uses sulphur (sulphuric acid) and cyanide compounds. So they stink. Cyanide is probably not used in "home kits", but that forces them to use some other stinky stuff.
