Nylon net scrubbie (dry) and elbow grease.

how about wash them with a special detergent at a temperature of 75 degrees
i'm not sure

Here is a link that might be useful: alcohol wipes

I'm afraid the corrosion may be permanent. The same thing happened to me. The only solution is prevention by removing the salt and washing the salt shaker after each use. You can try polishing the lids with a good silver polish. If that doesn't work, take them to a jeweler or other business that can resilver them. Mine was past hope which was sad since it was a wedding gift from a dear aunt and uncle. Good luck!