Cleaning horns on Avantgarde speakers?

A belt sander, with #30 grit should do the trick nicely!
;-)

Good luck with your project!

My friend has a full Avantgarde system with trios and solos for surrounds with some basshorns, he was told by avantgarde to use car wax as they use auto paint for their colors and it works well, his horns look awesome!

Honda spray polish and micro fiber cloth spray polish on cloth. Polish away after coating easy to just dust with MFC.

Do you use Armorall on the backs and poles or is it easier to get them detailed for you.
The wax without cleaning will be a way of cementing in the dirt. Try a small amount of car soap in water scrub lightly with chamois then rinse off the soap but the rinse will make a scene. I always used to use a hose.Dry with your wifes favorite bath towels white or ivory colored are best. Apply the faintest smear of wax let it dry completely. Then use dry chamois to buff avoid the gyro buffers they leave swirls .I like McGuires but the German wax is better they say . I found it to be a PITA.

sounds to me like he only wants to clean the dust off them. I think a damp cloth will do the job quite well.

Spray Windex on cloth and wipe. Will work the best of above said.

Microfiber cloth for dust, then use automotive wax once a year or so to protect the finish (am assuming the OP's speakers are just dusty, not dirty); must be careful not to grind in any abrasive dirt. Treat them just like an automotive finish (which they are).

STOP! First off all do not spray any thing directly to horn as it could get in or on driver. If using a spray wax spray to micro fiber fiber cloth then buff with a dry micro fiber cloth.Find out what kind of automotive paint they are painted with Most likely they are painted with base coat clear coat so use a wax appropriate wax for clear coat I like to use a spray wax called ICE you can get in any automotive store or at the marts. Since you are not driving these down the road I wouldn't worry to much about dirt build up but if it looks like it is embedded with dirt use a cleaner wax for clear coat if it is painted with clear coat.This requires a little elbow grease as a cleaner wax works out the haze and dirt by buffing the wax in with the applicator pad in a circular motion lifting the dirt out (note make sure the applicator pad is damp or pre moisten working wax on pad first by hand never put a dry abrasive object on a high gloss finish) I would prefer to do them with the spray wax simple great results.

I don't think it's so much the product as the technique and tools. If you wipe or wax a dirty or dusty finish, you're going to produce scratches, or at least swirls. I suggest using Griots Garage Speed Shine with microfiber cloths. It has a lubricant, cleaner and wax in one product. Just spray a little on the cloth (not the speaker, unless it's a very large area)and wipe gently in straight lines. I think that will be enough protection for something that never leaves the house. I use it on my Viva, which has an automotive finish and the results are excellent. If you order it from Griots, don't forget to order the sprayer as well. As an added bonus, it will work beautifully on your car as well.

Trust me the honda spray polish works amazing they should include some when they sell AG. And is only $7 bucks a can no sprayer needed. I owned AG horns plus many many others mostly with painted finish. Nice thing about the honda spray is it filters UV light. Is anti static since ment for use on plastic as well as other painted surfaces. The car waxes others mention might not be best for plastic. Since HSP is anti static less dusting after and very easy to remove dust after treatment without swirls etc in paint like more extreme treatments like car waxes. Another tip for record owners HSP works great on old LP covers cleans coats fills in scratchs removes sticky ladels or price tags plus all the old crap found on 20-50 year old record jackets. Again its anti static doesnt damage used this on LP covers for over 15 years now. Not for use on records just covers.