I've had best results with Craftsman circlip pliers.

Forget about Harbor Freight, Kragen, or other POS tools...you get
what you pay for when it comes to circlip pliers.

Once you get the clip off, you need to pull the piston pin.  This is fun also.

An easy way is to use a long 3/8 threaded rod (available at any
hardware store), put it through the pin then place a nut on the end
while the rod is between the pistons (use a small telescoping magnet
to help get the nut on since there is no room for your fingers).

Put a sliding weight from a dent puller onto the threaded rod and a
big washer and nut on the other end.  "slide away" and the pin will
come out.

If you don't have a dent puller weight use a piece of pipe or even a
hammer to bang on the washer end and pull out the pin.  It will be
tough at first but will come out with a few medium blows.  The 3/8
nut is big enough not to go through piston pin but small enough not
to get caught up on the other circlip.

>
>>  What's the secret to getting these things in and out (the circular wire
>  > clips that secure the wrist pins in the piston)?
>>