Knead together half of the white putty and half of the colored putty from the custom earplug kit. The result should be a complete mixture of the two putties—mix until the new color is streak-free. Each half will be used to form a plug for one ear.
Roll the mixture into a ball, and immediately press the mixture into the outer ear, applying a small amount of pressure to fill your outer ear cavity and create a smooth, outer finish. Be careful not to push the material into your ear canal. The putty should rest against the opening of the ear canal for maximum noise protection.
If you want sound protection only, this is the final step.
You can add earphones to your custom earplugs. First, remove the rubber or plastic covers of your earphones.
Insert the earphones into the putty as you would if you were listening to music. Treat the putty as if it replaced the rubber part of your earphones.
Wait 10-15 minutes for the casting to set.
Remove the casting by twisting gently. Trim off any excess pieces to create a smooth surface. Drill a small hole through the earplugs so sound from the earphones can pass through.