Is there an easy way to remove silicone sealant?
I've used a craft knife to cut out most of it (being careful not to damage the surface), then a small (2") putty knife to scrape out the rest.  Nylon scrubbing pads (the ones made for cleaning non-stick cookware) are great for getting rid of any last traces of the old caulk.

A chisel would work, but chisels are supposed to be very sharp, so I'd be very careful not to scratch whatever surface the caulk is applied to.  A putty knife isn't as sharp so it would take more work on your part to do any damage.