Classic & Vintage - Dulling Aluminum

Does anyone have any tips on dulling aluminum that doesn't involve paint. I am restoring a bike and most of the part are that sort of dull aluminium finish from age (which I kinda like), but I had to get a new seatpost. And it really stands out. Nice and bright. Any ideas?

not anything I'd do myself, but short of blasting it (best, most even finish) or scuffing the shine with scratchy pads or fine steelwool...I'd try chemicals. Either a strong acid (white vinegar?) but better yet a strong base (lye would be strongest, but most dangerous) so maybe back off from that a little and try dipping it in a solution of washing soda/water. Just a guess, but I'd bet that could get it looking "artificially aged" pretty quick.

Oven cleaner with a strong caustic soda content|(10%) might do the trick. I just de-anodized a black stem with it. It was quite dull before I polished it.

I agree with Ziemas. I have used household lye (caustic soda) from the grocery store to prepare aluminum for painting. It leaves a matte finish. Oven cleaner also contains lye and you probably have it at home already. Be sure to degrease the part thoroughly to get a uniform finish.

... and use appropriate safety precautions. Rubber gloves, protective eyeware etc.

Blue Magic Metal Polish on all your other aluminum (and chrome) parts. :D

Be sure to degrease the part thoroughly to get a uniform finish.

I haven't tried it myself yet, but from what I have read, a strong alkaline solution(lye) makes a good degreasing agent.

I would still want to start out with a clean part. Even if the lye will remove grease, it will start working on the clean surface first and perhaps leave marks where any greasy fingerprints existed. Also, start with a fairly dilute solution to see how it progresses. To dilute strong acids or bases, always add them to the water, not vice versa, or they will spit back at you.