So when I got my 2007 XT225 home one of the first things I noticed in the garage - having purchased it at night - was the fork tubes looked a wee bit rougher than I thought when I picked the bike up in San Diego.
So I did some Internet searching and found a great video on YouTube of how to clean aluminum rims on an automobile.
Applied the basic concept to the forks.
Use 1 part distilled white vinegar
1 part isopropyl alcohol
and Steel Wool - fine or 00
Do wear rubber gloves! the mixture is acidic
Do place paper / rags under the work area the mixture will stain concrete
Oh - and don't use any plastic bowls that belong in the Kitchen. They will be a bugger to clean out afterwards!
Start at the top of the forks as the liquid will run down and help pre-soak the lower portions of the forks.
You may need to use a lot of pressure on certain areas. Keep scrubbing until you get the finish you are looking for. In my case this was a test. I'm happy but will revisit the process when I remove the front wheel for service. That will provide better access.
This is a 'before' view of the forks.
This is an after
Note: your results may vary. The good news is just about any degree of pitting / oxidation can be removed. Wish I knew about this when I lived at the beach with my Virago 750. Could have cleaned that up nicely.