G'day MM and Norm,
The easiest way to get the catchers apart is to start at one end, the front and unclip the first locking tab with a screw driver then
wedge another screw driver inbetween the two halves so they can't lock together again ,then do the next clip and wedge another
screw driver inbetween the 2 halves and keep going until the catcher halves are apart.
If you just want a quick fix for the catcher you don't take it apart but just screw some plastic mesh over the outside edges
of the air discharge vents.
Cheers
Max.
