Restore HP-29C yellowed case

[PANAMATIK]

See this thread: http://www.hpmuseum.org/forum/thread-4211.html

You have to clean the case very carefully and rinse with distilled water. The main problem with bleaching is that there can occur irregular patterns with different brightness. Don't bleach too long, this inceases the possibility of irregulartity. Sunlight is not necessary, but it accelerates the process.

Bernhard