Being a newbie, preventative maintenance for me would usually be not touching the mechbox at all.
Regardless, I've followed the MechBox.com guide to opening up a TM M733 up to the part about pushing out the retaining pin for the trigger. The retaining pin on this doesn't want to come out, and I certainly do not want to damage it. I think this might be caused by the paint job on the gun. Any advice on how I can open this further without creating more worries for myself?