Anyone have experience removing rust from stake pockets? Have tried cut down flapper discs but it didn't get into the corners. Tried to sandblast but couldn't get to the 2-3" in the middle.

 

I'd just spray one of the rust coatings down in there and let it do the job.

 

Try navel jelly.

 

If the rust is built up, I'd scrape off as much as possible then treat with a rust coverter like Ospho, Metal Ready, Picklex or any of the phospheric acid products then spray in a good rust preventative paint.

I don't think navel jelly would work too well. If I recall, it's much thicker than Ospho so would be hard to get a good cover in hard to reach places.