Yea, we're not on every day but we get around sooner or later...
To remove the center cap without damaging it is sometimes a gamble. The original caps were not the best quality plastic and after nearly 40 years they've become brittle. First, put masking tape on the spokes so you don't accidently scratch them in the process of removing the cap, then get a wide blade stiff putty knife and work under the cap trying to get near the center. You must push the handle of the putty knife away from you (towards dash) to pop the spring button loose from the wheel. If you pull the handle towards you (away from dash) you may break the plastic nubs off that hold the cap assembly together. Just work a little at a time all around the cap and it will soon pop off.
If it doesn't survive, let me know. We can possibly repair it (depending on the damage) or replace it with a new one. Hope this helps and good luck.
Please feel free to contact me anytime if you need some help.
Dave
812-593-4328
WWW.RIM-BLOW.COM