Case yellowing - interesting read

[Frank Boehm (Germany)]

http://www.vintagecomputing.com/index.php/archives/189

(to sum it up: you can slow the yellowing, but once it's there, you can't do anything against it...)

[Katie Wasserman]

Thanks for that pointer, right up my alley! HP mostly used dark plastics for their old calculators, but yellowing is often a problem on the Woodstock and Topcat cases. It's a bigger problem on the 9815 case, the plastic seems really "cheap" and is very light in color.

I like the sidebar on the Magic Erasers, I need to give them a try when cleaning old calculators. I usually use Novus #1 plastic cleaner along with 99+% isopropanol to get off the really nasty stuff like ink stains.