Assuming that you can rebuild simple mechanical devices, without step by step instructions, here is what you need to clean your 488. You do NOT have to remove the quick release head assembly to clean your 488 ballhead, you can do a good job using "cotton swabs". You will have to disassemble the rest of the ballhead however, so first thing to do is remove the ballhead from your tripod.
You will need the following tools to disassemble the ballhead - 2mm "Allen" wrench, medium or large flat head screwdriver (#2 I think), large circlip pliers that close when you squeeze them (I actually used a pair of needle nose pliers instead).
Remove the "Pan Lock" screw. Insert the long end of the 2mm Allen wrench in the hole you removed the Pan Lock screw from. Rotate the panning base until you locate a hole with the allen screw, at the bottom of this hole is a 2mm set screw, loosen this set screw 3 or 4 turns, it is not necessary to remove it.
At the bottom of the ballhead assembly there is a hole used to mount the ballhead to the tripod. Insert the flat head screwdriver into this hole, and turn the captive screw clockwise to remove the panning base from the ball head assembly. Remove the circlip, and then lift out the captive screw, plate and washer. Just grab the screw and all of these parts willl come out at once.
Look carefully at the next parts, see how the "Ball Lock" screw aligns with the slot in the next parts? You will need to remember this when reassembling the unit, take a photo just in case you forget. Remove the "Ball Lock" screw.
While holding the ball head assembly in your hand, remove the circlip and set it aside. Now insert a finger or two into the ball head assembly and press down (push the stack of parts against the ball so they won't fall out as you turn the ball head assembly right side up). Carefully lower the stack of parts out from the bottom of the ballhead assembly. The top part should be a rubber "O" ring that fits in the top of the cap assembly you just removed. The "O" ring and the top of the cap assembly should be clean and dry. If they aren't clean them. You can also clean the ball, and the housing at this time using cotton swabs. Some internal parts of the 488 are greased, these are the roller pins inside the stacked cups that you lowered from the ball head assembly, and parts of the panning base. I used a multi-purpose grease to lubricate mine, and it works fine.
Reassembly is the opposite of the disassembly process. Insert the cleaned cap assembly with "O" ring on top in the machined groove, into the ballhead and press against the ball. Turn the ballhead assembly upside down. Make sure that the slot in the bottom of the cap assembly is aligned with the hole for the "Ball Lock" screw. Insert the "ball lock" screw. Install the circlip, making sure it fully seats into it's groove. Install the captive screw, plate and washer. Install the other circlip, making sure that it fully seats into it's groove. Install the panning base turning the captive screw counter clockwise to install. Adjust the tightness of the panning base with the captive screw until the panning base turns smoothly, and the ball head assembly will not rock side to side on the panning base. When satisfied with the fit use the 2mm allen screw to tighten the setscrew under the "Pan Lock" screw. Now reinstall the "Pan Lock" screw.
Congratulations, you just refurbished your 488 ballhead.