Best practices - cleaning contacts!

It really depends on the material that your contacts are made of.

If your contacts are gold plated, than cleaning is very simple because gold is not reactive and does not oxidize or corrode. The major contaminant that coats a gold surface are hydrocarbons, although there may be some salts that are on the surface from hand contact. None of these are chemically bonded and are easily removed with any alcohol; methanol, ethanol, or isopropyl. More aggressive cleaners are not needed for gold plated contacts. 

If your contacts are copper, silver, brass or another metal than a more aggressive cleaner like Deoxit can be used.

Sorry for the aside. Yes When I first get a CD. I polish the surface with the plain Viva. Two sorts of CDs. 'Dry" and "slippery. New come in two sorts. The dry have a great deal of stiction. rubbing them reduces it. Then I use a silicone slippery stuff to make them super slippery. It is a very old AudioQuest product I bought a box of.100 packets. I dump one packet into a cotton cloth and it is good for about a year. The already slippery I rub anyway, and use the cloth.          
I also polish damaged CDs using Meguiar's Scratch X and the Viva paper towels. Works for small tiny scratches very well. Larger too, if I work at it for a half hour!      
I also paint the outer edge
Back to the regular program..... 

Wow!  I am amazed!

Sounds like a good winter project.
Thanks to all for all the good advice.

cheers,Margot