novice question: pentosin

[steveb@cme.nist.gov]

Okay.. I was buying Pentosin at the parts store today and there's
two kinds.  (7.1 and 11.1S or something like that).  I believe the
latter is synthetic.  It says on that label "do not mix with Pentosin
7.1!"  I found cans of both types in the trunk of this car.  Uh oh.

I'm swapping the steering rack; I may as well flush the whole system.
How?  I saw someone mention the "Pentosin flush" but I'm not sure
what the procedure is.

Also: I bought the regular stuff.  Right choice?

Thanks,
Steve