Hepvo waterless trap problems

This video was taken when the drain in the RV was not draining properly. We all do dishes here, and sometimes things slip down the drain. These particular valves need to be maintained. Here is ours than needs a little TLC. Easy to remove, easy to clean!

[robh]

I have one of these valves in my RV and I can't access it to take it off to clean it. Can I put a soft bristle brush down the sink drain to loosen the debris or would it damage the flap when going past it and then pulling the brush back out? Or, is there a better way to accomplish the task that I should try?

[johnwalsh]

Just curious but was this fitted vertically or horizontally?