If you be smart with water, if necessary, to make fire. Here are some possible methods to do it:
You need to take the old bulb, remove the bottom cap and everything inside to an empty flask. Wash it, the glass will be crystal clear. Fill the flask with water, close the hole with the help of a balloon. Had a wonderful lens. Hold it over a sheet of paper to focus the sun's beam, and soon he was on fire.
Take a small container, put into it a piece of transparent polyethylene film so that it took the form of dishes. To pour water almost to the brim. Then collect the edges of the polyethylene and loop them, so that wasn't inside of emptiness – came transparent sphere, which can be used as a lens.
If you find a clear plastic bottle with rounded shapes, it also can be useful for kindling a fire. Just find a bit of dry grass and turn the bottle upside down so that the sun's rays focused on a point.