If my husband and I come upon a cache in ill repair we will try to repair it. I carry replacement ziplock baggies and log papers as well as some macro/small camo-ed bottles.
Recently we came across what was supposed to be a cache but all that was left was a wet log in a torn ziplock hidden under some pine cones. We replaced the torn ziplock, added new dry log papers and since the cache was near a hospital the cache container was replaced with a medicine bottle, hidden at the exact co-ordinates as the original. We noted what we did in the online logs so the owner would know what had happened.