If you post an adoption request note on each of the geocache listings as a 'write note', or in the body of the listing itself, that will alert future finders that they are available for adoption. Alternatively, you could go and remove them and archive the listing thereby freeing up that spot for someone else to use to hide a new cache. There's nothing saying they have to stay forever!
These caches are the only ones around for many kilometers so I don't want to archive them because they will not be replaced.