NOS Grace F9E question

A friend of mine gave me a Grace F9E to try on my 1200G.  He thinks it may be a good fit.  It appears to be brand new and never used.  It has a plastic protector that covers practically the entire cartridge.  I cannot get it off as it is on there very tight.  Is there any special way to get it of and not damage the cartridge?

Any suggestions would be appreciated.