I had the same problem this Spring. Last time I checked the rain bucket, it looked like an unflushed toilet, really disgusting. Anyway, I got it all cleaned up, tore off a length of black electrical tape long enough to wrap around the circumference of the bucket. Lay the tape down sticky side up, then lay nails about 1.5 inches apart, perpendicular to the tape with an inch to inch and a half of the pointy ends hanging off the edge of the tape. Wrap the tape around the top of the bucket with the edge of the tape even with the edge of the bucket. No more crappy bucket! Also, I pushed nails through the tape from the sticky side, then applied this "spike strip" to the top edge of the solar panel, because they were sitting here and crapping all over the solar panels. So far so good! I'm now running a clean operation....