Talc the map now!
In a thread about slavery spelling/pronunciation, someone wondered what "telt" / "talc" (the clear plastic sheeting you cover maps and other things with) really was.
I pondered over this for a while, and then suddenly remembered that I'd hit upon the right answer years before in a brainwave - it's actually "tarp", short for "tarpaulin". Many are resistant to this idea, since they think tarpaulin must be opaque and thick, but I've dug up many graphic illustrations of clear plastic tarp:
DEKE - Cornell
Thoughts on Restoring a Morgan
Introduction to Media Blasting
Healthy Lawns—Site preparation: Soil solarization
57 Ways - 15. Solarize Soil
WAN in Lab: Facilities: Pictures and Schematics - gallery: \WIL\2004-12-09 Adjustable Shelves + Corning Fiber Spools + Plastic Tarp