Do you find wandering dogs and cats in your neighborhood? Inform animal owners that they must prevent their cats and dogs from wandering and roaming freely to keep them safe. It's easy and anonymous. Just put the appropriate door hanger on a door or gate. These free, downloadable PDF files are designed to be cheap to print and handy to keep with you at all times. Each prints on 1/2 of a standard letter size sheet of paper. Just print the file and then cut the printed sheet into halves and cut out the doorknob holes. If you live near Spanish-speakers, print the Spanish language version on the back side of the English-language version. You might not know which language the household speaks but with one language on each side you can still communicate. See the images below.
"Loose Dogs" and "Loose Cats" on one sheet (see images above)