I'm assuming this horn is silver plated? Tarn X works wonders on silver. You can buy it at Walmart or most stores for around $5 a bottle. You'll want to remove the keys first. Then pour enough Tarn X in a cup that you can dip a small paint brush or a tooth brush in it in it. I use a tooth brush for most of the body, but a paint brush is nice to get in around the tone holes and the posts. You'll be surprised how quickly it will remove the tarnish....in a matter of seconds. After the tarnish is gone you'll want to rinse the horn really good in hot water. This is why I recommend removing the keys first. The water will ruin the pads. I suppose if you intend to replace the pads anywat, it's not a big deal, but it's much easier to clean the body without the keys. After rinsing the horn and drying it off with a towel, use Wrights Silver Cream to polish it. Use it sparingly. I also use Wrights to polish the keys. Buff off the polish with a rag. If you use too much polish you may need to rinse the horn again. Just dry it and buff it with a rag after rinsing. It will clean up nicely. I'll be happy to send you some pictures of a couple I've restored. Jim