Found this on my bottom board

[shakerbeeman]

[Robo]

Looks like the m normal stuff (pollen, wax flakes, brood cappings, etc).   Are you using a screen board on top of the bottom board?   Usually the bees keep the bottom board cleaner if they have access to it.

[shakerbeeman]

Thanks Robo. As a newbee I had hopes this was normal and not some remnants of robbing which I don't think has occured. The picture is not very good but what is there does look like what you describe. I do have a SBB above a solid board and that is why the stuff is building up I suspect.

[Robo]

One thing to keep an eye on is that this is haven for wax moths as the bees can't get access to this area.  It is not normally a problem for strong hives,  but they can easily devastate a weak hive.

[shakerbeeman]

Good thought. I had been thinking about making some narrow device that I can scrape out this stuff with. With the wax moth problem it makes it that much more important to keep that area clean.

[tillie]

I'm in the south, but even beekeepers in your part of the country open up the SBB in the summer.  I don't think you need the bottom board....but I'm a relative newbee, so I may be wrong about that.

Linda T in Atlanta

[Brian D. Bray]

I don't even consider using anything to close up the screened bottom board.  I find that using a slatted rack provides sufficient thermal barrier to keep the hive fairly warm even in winter and letting the debrie fall through to the ground where the ants and other insects carry it off works well.  Keeping the SBB open seems to help in keeping the ants and stuff out of the hive because the feeding station is below the hive on the ground. 
With the use of the slatted rack and the SBB I have little bearding problem even in warmer weather.