Cleaning horns on Avantgarde speakers?

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.