This is a FYI post for future searchers.  I am just posting my
experience because I couldn't find much.  I did find some info on this
group, but had some problems. Although I rarely make disclaimers, in
this case I will.  Do not remove your foley cathether unless your
doctor told you that you should, and has given you instructions.

Our dr gave us the syringe, and put it on the little fork of the tube,
and demonstrated drawing out the water.  Said it should be about 10 ccs
but to continue to draw until no more would draw, to be sure the
balloon was empty.  Then, my husband was to take a deep breath, and as
he was letting it out, I was to pull the catheter out.

That part went fine, easy, smooth, but it took a while to get there,
because no water would draw out of the balloon.  *Maybe* half a cc.  I
could tell it was 'drawing' because there was resistance on the syring,
but the water wouldn't come out.  I had visions of the little side tube
that fills/unfills the balloon being clogged or otherwise non
functional.  I tried cutting off the valve and drawing that way; no
luck. Nothing.  Terrified of trying to pull the cath out with an
inflated balloon.  I cut the big tube, don't do this.  However, I had a
syringe with a needle and that fit into the little ballon side tube.
Still no water coming out.  By now it was 8 a.m. and we called the dr.
He said, "try pulling it out, don't force, just pull gently." It worked
as smooth as silk.  Apparently, sometimes the balloons leak into the
bladder and do not have the full compliment of water.

It was really easy and would have been no problem at all if I hadn't
been trying to find that 10cc of water that wasn't there at all...