tough sausage casings

[DanMcG]

I made up a batch of smoked hot links using the same method as always but these have a very tough casing. I'm not sure if it's the casing or maybe the humidity while smoking but is there a way to soften them up? I was thinking steaming or boiling them at low temp might work. or maybe even pickling them.
Any suggestions are appreciated.
Thanks, Dan