Rain Gauge Spider and Wasp Repeller

I have an AcuRite wireless rain gauge (less than $25 on Amazon) that works very nicely, but unfortunately is an extremely attractive home for spiders and mud dauber wasps, which build webs and/or hives that restrict the movement of the tipping bucket. Over the years I have found that moth balls or urinal cakes work nicely to repel various pests and decided to try them in this situation as well, but needed some way to hold the mothballs without interfering with the tipping bucket and limit the d