See if you can find some Tact-tiles. I draw maps ahead of time and sometimes they aren't used for 3 months, but I can still take off the marker with a little effort.
Or run out to a print shop (like kinkos) and print out a dozen of each in a 1" grid on regular paper: 36"x48", 30"x42", 24"x36". They are all standard sizes, and everyone with a pen, pencil & marker can draw on it (useful for area of effect spells where players can mark with their own colors). The sizes allow for ease of fitting on a table with books, etc. You can mark out specific dungeons, terrain, and encounter locations in advance. With a ruler and a thick marker you can draw what the characters see as they venture into a dungeon, and you don't have to work about smudging the work.
If the battle needs to be saved, just draw where everyone was at, and write the names down. You can even keep initiative & spell durations in empty space on the side. Once you are done with it you can keep it or recycle it. I try to keep mine as the characters have a habit of revisiting places and seeing the scares of past battles on the site. Plus it lets them know that whereever they are is a potential encounter... even places visited in the past.