Bench slots are very valuable to a team and can mean the difference late in the season.
Take a good look at the players you have on your hitting bench and compare their statistics to those of comparable players on the waiver wire. You will quickly see that equal quality players are out there for the taking. Whatever reason you have for keeping them is not as good as the reasons for clearing them. The same players are on the waiver wire. If you don't want someone else to have the players, let them.