If you can't find it, use a throwdown. Log posted for a cache I found recently:
"We are on a 23 county quest and dont have extra time to hunt for caches that either aren't there or coords off. We looked around quite a bit first. We put a cache at the correct coords in the trees. If someone wants to hunt for the original, go right ahead. This is our XXXXXXX county cache."
The original cache was there and reasonably close to the coordinates (I redacted the county name).