Tripods and saltwater are a bad combination. Here is a breakdown of the cleaning process I use whenever my tripod has been in the ocean.  The tripod is a Gitzo 3532s, but the basic principle is the same for all tripods.

Make sure you have everything you need: 

Starting at the bottom leg joints, unscrew the twist locks all the way, you can now slide the bottom leg section out. Remove the 2 white plastic guides and slide the twist lock off the top of the leg. Repeat the procedure on the upper leg joint and the other legs.

Now we need to remove the bushes from inside the twist locks, if you look in the wider end of the lock you will see one of the slots in the bush is cut right through. To remove the bush from the lock you need to pop out one side and overlap the bush on itself., it can now be removed from the twist lock.

Pull off the rubber spike covers and unscrew the spikes from the bottom leg sections.

I leave the upper leg sections mounted to the spider and stick it under the shower for 5 minutes. After that I remove the head mounting plate and allow it to dry. Either dry it in the sun or use compressed air if you have it. I forgot to take pics of this step. 

WIth the legs stripped down we can start cleaning the parts. (At this point it would be a good idea to find a better spot for your beer, I spilt mine on the parts and had to clean them all twice).

I put all the parts into a tub of warm soapy water and use a toothbrush to get into the tricky places. Make sure you get all the dirt out of the bushes, if these aren't completly clean the legs wont extend smoothly.

Use the WD40 to break down the old grease on the twist lock threads, give them a good scrub with the toothbrush and rinse them in the soapy water. Dont for get to do both threads, the one on the leg and the one inside the twist lock.

When you've finished cleaing everything you can either leave them in the sun for a few hours or hit them with some compressed air, everything should be completely dry before reassembly.

Apply some armorall to the lower and middle leg sections, just wipe it on and wipe it off with a clean rag. This will make the leg action nice and smooth. Let the legs dry completely. 

Insert the bushes into the twist locks and make sure they are seated in the groove the whole way around. 

Slide the twist lock onto the lower leg section, and place the white guides in their locator holes, hold these in place as you insert them into the larger leg tube. 

If you look inside the tube of the middle leg section you will see a ridge, this needs to be aligned with the gap between the white guides. 

Do the same for the middle leg sections and the other legs. Before screwing the twist locks together we need to apple some grease to the threads. 

Dont put too much grease on, you dont want it to ooze out when the twist locks are done up, make sure the grease is only applied to the threads, do not get any on the leg tubes. Spread the grease around the threads with your finger, it doesn't have to cover the whole thread, it will even out when the twist lock it tightened up.

Put the spikes and covers back on the bottom of the legs, I have the sand feet on as I'm about to head to the beach for a shoot. Do them up reasonably tight so they dont come loose. 

Thats it, were all done.