Spy watches conceal spy gear like secret notes, flash cards and money. An old watch that is sitting around gathering dust can be turned into a camouflaged container.
Open your watch. This is usually done on the back by inserting the jeweler's screwdriver under the lip of the circular back panel and prying it off. Pull out the insides and be careful not to lose any of the pieces. Put them into a convenient location, such as an empty medicine bottle.
Inside the back panel is a part that fits around the inside of the watch and grips it. File down this ring-shaped grip so it fits more loosely into the back of the watch for easy removal. File the lip of the watch where it contacts the back of the main watch so that it angles upward and is easier to pry off with a fingernail or other object.
Pull all knobs or buttons off the "guts" of the watch and find their original location on the watch. Hold them in their original location with tweezers and hot-glue them into place. Glue the pieces from the inside of the hole that they are going into so the glue doesn't show.
Take the rest of the guts to a print shop. Set the watch face guts onto a color photocopy machine. Do not reduce or enlarge the photo. If the watch is black and white, you may be able to get away with a black-and-white photocopy, but color photocopies work better.
Cut out the photocopy and place it into the watch so that it looks like a normal watch to the casual observer. Put a layer of hot glue behind the paper to hold it and to waterproof the paper. Make the glue layer thin so it does not obstruct the item you intend to conceal. Also make sure that any other holes are covered with glue to help seal them from leakage.