Punch a hole at one end of each lid

Punch a hole at one end of each lid.
Thread each hole with a length of yarn and knot the ends of the yarn together to form a loop for hanging.
Spread petroleum jelly over one side of each lid.
Take the lids outdoors on a windy day and hang them in various areas.
Leave them outside for about an hour or two to collect what may be blowing in the wind.
Retrieve the lids and see what they have collected.