Here is a great video with clear instructions and video that you can use if you need to restring your horn. I recommend the yellow Yamaha string, a small screwdriver (1/8 in.), and very sharp, sewing kit scissors.
I have included links to Amazon because it is often the easiest option for families picking up supplies. However, you may want to shop around for the best price. There are many online resources besides Amazon (see my resources for students page).
Al Cass Oil
Use this very light oil often and regularly. Apply one drop under each valve cap, and 1-3 drops into each slide. Apply every day or at a minimum twice a week.
Use this heavier oil only on the back side of your rotor valves (NOT in the slides or under the valve caps). Place the needle in the crevice at the base of the large screw that rotates (in the space between the axle and the bearing) and squeeze the oil bottle to apply 1-2 drops for each valve.
Schilke Tuning Slide Grease
Use this grease on all of your horn’s slides. There are many great grease choices out there; this one is one I like because it seems to “stick” well. I suggest you apply grease every other week. First, remove slides from your horn. Then, wipe off slides clean with a paper towel (not facial tissues). Apply a small amount of grease to your thumb and finger and lightly coat slide with grease.
There are several different companies who make mouthpiece brushes that should be fine. If they look like this one they should be fine. Yamaha, Bach, etc all make similar ones. Use with warm soapy water every other week. Scrub the brush in your mouthpiece to clean it, but avoid scratching the mouthpiece with the tip of the brush.
Use the snake brush to clean your lead pipe. First, remove your mouthpiece and first tuning slide. Then, push the brush through the length of your lead pipe to remove “gunk.” Clean every other week. Brushing your teeth before you play will also help minimize junk in your horn.
You may want to consider getting both brushes in one package if you need both.
All maintenance supplies:
If you need everything, you may want to pick up this handy kit that includes it all. Please note that the oil is synthetic. Since synthetic and natural oil don’t mix, you must first completely wash the inside of your horn if you switch between the two.
Where To Oil Your Horn:
A drop on top beneath the cap
In the slides on the side
In the crack at the back
Often, students and their families have a string break on their French horn, making it impossible to use the horn properly.
Although you can take it to a local music shop to be repaired, you may want to consider repairing it yourself. It takes a bit of time the first time you do it (I would plan on about 30-60 minutes if you've never done it before). You also need string and a few tools.
However, once you've learned how to do it and have all the tools and supplies you need, it will take you only 5-10 minutes in the future, and will save you a trip to the repair shop.
This youtube video posted by a band director provides a great tutorial on how to do the necessary repair. You can buy the string you need for the repair online, including at Amazon.
Horn teacher and performer