Is it safe to remove PC (polycarbonate) arms from minfigures? I would like to replace the clear PC arms on the Chima ice figures with opaque ABS.  Would I still be able to use the clear PC arms with other figures after I have removed them?

I know that removing and replacing arms makes them slightly weaker and can only really be done once, what I am interested in is the relative durability of PC and ABS in this regard.
The clear PC arms are more brittle, however you should be able to replace them at least once, since the torso you are placing it into is ABS - so there is a bit of a give/flexibility on that side. 

One thing to be careful of, is when you take out the PC arms (and when you put them in a new torso), do not hold the arms by the hands! This will put pressure on the wrists and can make the more brittle PC plastic crack. Either hold the arms further up, or even better, take out the hands first, then the arms. Hope this helps.