I'm not sure what it is that you want filtered out, but it seems to me none of the BBS's built-in options are going to do much for you. Turning off avatars and changing the thread view to "flat" might help out, but that's about it. If you want to, say, strip the header and footer away from the BBS, that's not going to happen without some custom script to do the filtering for you.

At one time I thought about writing a little script to extract just the text from all new threads and display it in one, easy-to-view web page, but I never got around to it. That sounds like what you'd want on a mobile device, then you could just open the "real BBS" when you want to reply to something.