Make sure your hole is.
Replace rotted fence post in concrete.
Position the lines above and below each horizontal rail.
Remove the old post.
If you have an old wood fence post that is completely rotted off and you are able to remove it along with all debris you could reuse the cement ball for a new post.
Using a small shovel to slope the concrete away from the post.
Set the depth of cut on a circular saw to cut through the posts but not into the rails.
How to replace fence post anchors in concrete or fence post spikes without concrete.
Use a sledgehammer to break up the concrete around the old post.
Some have successfully used fence post anchors.
This way the post will not be sitting in cement to rot off again.
Look for copper naphthenate solutions at home improvement and paint stores.
Knock out the wood between the cuts with a hammer.
Dig a semicircular hole around one side of the concrete pier.
Saw along each pencil line.
Break up the concrete.
Project step by step 5 dig the right size hole.
After putting the 3 bags worth of concrete into the hole and ensuring it nicely surrounded the post i used a small garden shovel to slope the concrete away from the fence post.
You can apply the solution by brushing it onto the post or dipping the post into a tub filled with the liquid.