Step 2: Find a bottle
Once you start looking, you will see bottles everywhere. You can recycle old jars or bottles from your house - salt shakers or clear glass spice jars work well. I like to find bottles in thrift stores or garage sales, or rescue them from the garbage.
I recommend a wide-mouthed container (such as a canning jar or spice jar) to start with - it's a lot easier than one with a narrow neck.
The bottles that work best are ones that have a tight fitting lid. This helps to keep moisture inside the container.