[TR] dried brake fluid?

[Paul Dorsey]

Although the labels of most spray brake cleaners said to cover rubber parts
and avoid contact with rubber the 3M Spray Brake Cleaner did not say this on
the back of the can, so I bought this brand.  While I sprayed it in the metal
brake lines and then blew them out with a air compressor (equipped with a
filter to remove water).
    However, I did not spray it into the caliper units themselves.  I didn't
do this for fear it might contaminate the rubber.  That is my question: should
I?  Of course, the Dot 4 Brake Fluid (which was new at the time, not been
driven, but dried within the lines since my system had numerous leaks several
years ago, it is this dried bake fluid that I seek to remove. I fear a buildup
of this crud.   I hope that by spraying it through the metal lines it has
helped to clean those lines.  The question remains:  should I spray this 3m
Brake Cleaner into the caliper units?

    I've also got the same question in regard to the  master and slave
cylinders?  I am also concerned about their rubber parts.  How much brake
fluid crusty crud is down within them?  Is this 'crud' (only 1-2 year old
brake fluid most of it dried) is this stuff that objectionable?

Thanks,
Paul Dorsey
60 TR3