I found this cool sponge caddy years ago. The caddy hung over the sink; it hooked over the edge of the sink. I could only reposition it on the left and right sides of the sick. The center wall dividing the double sink was too wide for the caddy to hook onto.
Another problem to this caddy were the tight corners. Food particles from the sponge would get stuck. It was very difficult to clean.
I happened on a different caddy design. The mounting mechanism relied on suction cups. This however didn’t work on my sink. That was the only flaw. I tried ceramic magnets, but that wasn’t strong enough. I then tried rare earth neodymium magnets. That was the perfect type. I used Sugru to affix the magnets to the caddy.
I now have a movable sponge caddy — I can affix this to any wall of the sink.
The sponge holder was around $6 from Target.
The neodymium magnets was around $4 (1/2″; 6-pack) from Home Depot.