Online local community classifieds
can give you maximum exposure in the area to keep an eye out for your lost items. This way you can increase your reach to the community to help you find what you have lost.
The same is true if you have found an item. Reporting the found items to the appropriate authorities or businesses will work if the person who lost the items inquires at those same locations. Posting an ad in a local community classified site will help increase your exposure to more people who may have been or know the person who lost the item you found.