Car wax will
not do it, as the chalkiness is oxidation, which is a chemical change in the metal, not a physical change. It is, in fact, the metal's way of protecting itself. It is a product of the metal being in water, in this case aluminum, being one of the less-noble metals (more vulnerable to corrosion), and salt water, much more corrosive than fresh water.
The only real ways to be rid of this are:
1. Regularly sand it down to bare (barer) metal and keep waxing it over, which won't result in a shiny finish and does involve removing some of the thickness till, some day in future, the metal will be unsafely thin. This will help if you're seeing distinct scratches, but if it's rather evenly over the whole surface this isn't a good plan.
2. Clean it, solvent-wash it, and paint it with true epoxy paint (Brightside, Perfection, Awlgrip; pick a color). This will seal the metal from the air (at least, on the outside, where it gets most wet) and stave off-- for much longer than sanding will do-- the oxidation.
The truth is that nothing short of removing the aluminum permanently to a dry, electrolytically-pure environment will stop normal oxidation.
If you are observing particularly localized splotches of whitish oxidation near some of the fittings-- internal-halyard sheaves, exit plates; the wear plates under Selden's toggle shroud attachments are a typical spot-- this is due to bimetallic corrosion, the effect of two metals being together in water. It's why you should not put gold-rimmed dishware or real-silver flatware into the dishwasher with common stainless-steel things, which, especially with caustic dishwasher detergent (a base), leads to a gradual pitting and a slow vanishing of the more-expensive but less-noble metals.
On your boat, the more serious bimetallic corrosion is actually much easier to avoid than the more minor all-over surface oxidation (which really isn't a problem at all, except aesthetically). As a quick stopgap (which actually works wonders), remove each stainless-steel piece, whenever you get to it, and cover its back with electrical tape (I use the white stuff, especially with white-painted spars). Then, reinstall it. Use electrically-insulating thread-locker (the semi-permanent kind at the strongest) on the screws. The tape will insulate the metals from each other, saving the aluminum, the less-noble of the two, from being eaten away.
There are other, more expensive ways to do this-- one excellent but costly recommendation is to coat the backs of the stainless-steel parts with Tef-Gel, at about $20.00 for a tiny tube, a procedure that needs to be done every few seasons. Figure on two whole tubes for one dose for the average 40-footer's spar. The tape will last for years and its failure mode is ideal-- it just gets crispier but stays in place and remains more or less an effective insulator. Those less concerned with finesse have been known to gob up silicone behind each piece too; but, as this adheres them somewhat, it makes a real mess to redo it (which it does need as ugly, stinky mold forms in the silicone).
As for boom bails and other pins through the spars, remove them and install fender washers of nylon (available at Lowe's) or Delrin (available at McMaster.com) between the stainless-steel tang or bail and the aluminum. If there are stainless-steel wear plates here, do as above with the tape. If not, consider overdrilling them and installing aluminum tubes through the raw holes like bushings for the pins (I would not do without this on any boat, especially on shroud-tang pins). Squeezing a little white lithium grease onto the shank of the pin in the process will help too.
Come to think of it, squeeze that lithium grease on the turnbuckle screws too-- like every month or so-- and on anywhere else mounting or moving pins of one metal are in direct contact with holes in another, such as on stainless-steel self-tailers on bronze or aluminum winches. Needless to say, aluminum should
NEVER be in direct contact with either bronze or brass (unless you intend your boat to be a kind of science experiment).
These measures can and
should be taken by everyone, especially
before seeing visible signs of oxidizing corrosion ('cause they'll help prevent it). The all-over whitishness you're seeing can very well be the result of a whole spar going slowly bad because stuff wasn't done like what I, and the higher-quality boating industry, recommend. Sadly, it's consistent with what I know of both 'new' (post-1983) Hunter and Selden to brainlessly recommend something like
car wax for something like this. It's like I so often say: sometimes the boatbuilder is not your friend.
Sorry if sometimes (most times) I don't provide the $2 answer but default to the $200 one. My bad!
