Insert a battery into your battery retainer and see what sticks up.

The topside battery pickup was the highest point here so I clipped it off to be level with the rest of the retainer using some precision snips

Next I used 220 grit sandpaper to gently wear down some of the high points of the plastic clips. Don't sand too hard or too much to avoid wearing these clips away entirely, we just want to reduce the points that stick up too high

Last picture shows before (left) and after (right)