Has anyone figured an easy way to clean the mineral deposits from hard water and males with poor aim off these soft plastic RV toilets? I use Listerine to clean the bowl. Kills germs, smells clean, and I don't have to store a special product. But every couple weeks, I still have to get at it with Lime Away and a nail brush. I hate that job, and sometimes there are more than a couple weeks between doing it. Then, that job becomes even worse.