If you haven't ever cleaned it out, I would definately do that.
The easiest way to pressure test it is to get a bicycle inner tube and cut it opposite of the schrader valve. Take each end (now open) put on on the inlet and the other on the outlet. Use some tie wraps or hose clamps to keep the inner tube ends on the IC. Use a pump or compressor and pressurize the IC up to around 30-40 psi and check for leaks. Use a spray bottle with some soapy water.....
High Tech...
John