Disposable cameras are great for using in places or situations where you might not want to take a more expensive digital camera. If it becomes damaged, it doesn't matter because of its low cost, plus you were going to hand it back for developing anyway. Rather than buying a new disposable camera every time you don't use your digital camera, you can easily reuse an old one and bring just the film in to be developed. This way, you will always have a carefree camera handy.
Remove all the stickers from the camera. This allows you to locate any potential release clips and exposes the seal connecting the back-plate to the camera body.
Pull the release clip (if there is one) to pop off the back-plate. If there is no clip, take a flat-headed screwdriver and pry the plate off by inserting it into the seal and twisting. You may need to apply this technique to multiple sides of the camera before it pops open.
Remove the developed film by pushing it up from the base. It will slide up slightly before you are able to pull it out.
Insert your undeveloped film by inserting the top end into the slot first and then pushing the base down into the camera. Make sure the start of the film reel is poking out toward the opposite end of the camera.
Pull the film toward the empty chamber (containing a cylinder with small slits--this is the spool) on the other side of the camera to where the film is now inserted.
Pull out the winding mechanism found on the outside of the camera (below the empty chamber). This will allow the spool to turn freely.
Insert the narrow part of the film into one of the spool's slits. Push the film in as far as it will go. It should now become hooked on the spool. If it doesn't, you can use a small amount of tape to attach it.
Re-attach the back-plate to the camera. Once snapped shut, turn the winding mechanism (you pulled it out in Step 6) clockwise until it will turn no further. This loads the film, ready to be exposed.
Push the winding mechanism back into the camera. The camera is now ready to use, again.