Also, saved clay tablets likely wouldn't have survived unless they'd been fired in a kiln. So why are all these tablets he saved still around? Two possibilities I can think of: - he wanted to keep them, so fired them himself, OR - he pissed people off enough that they burned his office down

if I recall correctly his house burned, but actually there are plenty of unfired clay tablets. Clay mostly keeps its shape even when wet as long as it doesn't get disturbed. I've found mammoth footprints in blue clay that were ~12 thousand years old next to a river, so they were plenty wet

Wasn’t it so you could sort of chisel the original message off and use it for another message?