Cleardrying adhesive for acetate/mylar sheets?

[phinnia.livejournal.com]

I'm looking for a way to display a postcard collection. The idea I had was to take a sheet of clear plastic (like acetate) and use that as a backing, and cutting another piece to size or slightly larger and making 'pockets' from it. (That way I can move the postcards around, and I can still see the backs, too). The only flaw in my evil plan is the glue. What kind of glue would I use? The pockets don't need to hold anything overly heavy, but they will need to be at least marginally sturdy; and I'd like it if the glue dries clear. What kind of glue or adhesive would be the best thing to use?