Palimpsests - revealing the past

Occasionally I see a word that just has to be used, somewhere - anywhere. Today's word is palimpsest. According to Wikipedia a palimpsest is a document that has been wiped clean and used again (comes from the Greek to 'wipe clean', roughly speaking). Cicero and his fellow Romans used wax-coated tablets that - you guessed it - could be wiped clean and reused. Sounds like a technology we could (re)use today. Historically speaking palimpsests are especially useful when we are able to decipher what was written before. One 'original' document may have overwritten a previous version, like the Christian churches scrubbing out and writing over pagan beliefs (if not adapting them to suit their needs). It's a window into the past.