I have 2 metal anchors embedded in my pool walls. They are there to clip a rope across the pool. Similar to these: http://www.recreonics.com/cup_anchors.htm
These anchors have corroded away and now the unplastered concrete behind the inserts are exposed.
I would like to pry the remaining bits of the anchors out of the wall. What is the best way to fill in the space where the anchors used to be?