A lot of people like to coat the inside of the drinking horn with bees wax to ensure you have a clean, easy to wash interior. This does mean though, you can only use your horn for cold drinks not hot. With a wax lined interior you need only rinse out with cold water, which is a great way to keep it clean if you are out in the fields in a camp ground over the weekend.
Its an easy process to coat your horn - simply wash out your horn and use the brush to reach the bottom, then fill the horn with sterilising solution (i.e. Milton or such as used for sterilising baby bottles) and leave overnight. Tip out the solution and rinse. Once the horn has dried fully, put the bees wax blocks in a cup and heat in a pan of boiling water until the wax has melted. Holding the horn upright, tip a small amount of wax in the horn and then pour directly back into the cup before the wax sets. Rotate the horn a little and repeat this until all the inside of the horn is coated in the wax. Once the wax has set your horn will be ready to use. Simply rinse out with cold water when finished. You can use the soft brush supplied to reach the bottom if needed while cleaning.