I placed a few players on the slow-moving, stagnant (?) trade board, and no-one has wanted them.
Should I just cut them now, or hang in there?

It depends, do you need the roster space to sign other guys? Are they young players that might progress even if they are inactive or on the bench? If they are older guys that you have no use for you can surely cut them but also remember if they have big bonus money cause you will take the remainder of their bonus as a cap hit this year and the next. As you get to know your roster you will find it easier to know what guys you might need to hang on to and let go :)

thanks - most of them are older guys - i'll check their bonuses as I sort of understand that too now.
I don't 'need' the space, as I can't find anyone to sign! The free agents are full of P and K players, and I've tried on the trading block a few times but without success.
So I was going to simply wait for the next batch of draft to come next season :(

if you go to filter you can search for all free agents without punters and kickers. You can also search by position and if you click the box it will allow you to see if players outside the position you search for are suited to play that position as well.

I usually try to post a message on the Trade Block forum whenever I have updated the players on my trading block so the other owner's know to take a look.

I don't check the trade block very often, so if someone added some new players and didn't post a message about it, I would most likely never know.