A clown's bright red nose is perhaps his most distinguishing feature. Clown noses come in rubber, leather and foam, each of which has its advantages and disadvantages. The advantages of a foam nose is that it is more breathable than rubber or leather and it can easily mould to whatever size is necessary. Foam clown noses can be purchased in a costume supply store but are fairly easy to make yourself. Making your own will save you money and allow you to fit the nose perfectly.
Purchase a red sponge ball from a local craft store or a craft supplies website. The ball should be approximately 60 millimetres wide. Purchase the sponge balls in bulk if you wish to make several noses.
Cut a small slit in the middle of the sponge ball, using sharp scissors or a craft knife. The incision should be deep, just under halfway through the ball, but only about 3/4 of an inch wide for this first incision.
Try the nose on the costume wearer by inserting her nose into the slit in the sponge ball. The material will stretch out as you open it to insert the nose. Though rubber and leather clown noses require the use of glue, foam noses mould around the nose and stay on without the use of any adhesives. Repeat this process until the nose fits perfectly. If the slit is too narrow for the costume wearer -- which is very likely after the first incision -- widen it with the craft knife.
Make careful, small adjustments as you fit the nose to the costume wearer. It is easy to make too large an incision, which will ruin the nose and make it unwearable.