First thing - seriously - give the belt and retract mechanism a good cleaning. 20 years of sliding in and out has drug all kinds of dirt, dust, gunk, etc into the retract mechanism and gummed it up.
Get yourself a bucket of hot, soapy (dish soap is fine) water and some clean rags. Grab a bottle of degreaser and another bottle of spray lubricant - silicon or something similar. Also a can of compressed air.
Pull the belt all the way out. Start cleaning the belt from the end closest to the retract assembly and work towards the latch mechanism. Lather. Rinse. Repeat. Several times.
You'll be amazed at all the dirt you pull from the belt.
Once you're happy with the cleanliness of the belt use your can of compressed air and give a few blasts into the retract assembly to knock loose some of the gunk. Spray a small amount of degreaser into the opening, then start pulling and releasing the belt - you only need to retract it in/out about a foot. You're wanting to get the degreaser working on the retract mechanism.
By now you should see a huge difference in how the retract mechanism works. Once you're happy, do it a few more times just because. Then - a light spray of the silicon lube and again work the assembly in/out about a foot to get the lube worked into the retract mechanism.
Then - do the same to the receiver - a little degreaser and a little lube. Work the (faded to pink) red receiver button and let the degreaser and lube do their job.
Then do the same to the passenger side because it needs it too.
Once you have both belts working like new again (they will - honest), get yourself a red permanent Sharpie marker and color in your faded to pink receiver buttons back to a nice bright red.
Clean up your mess, drop the top and take your Boxster out for a good spin. Come back home, open a San Miguel or two and congratulate yourself on a job well done.
