Historically, Egyptian women used wooden curlers and mud to set their perms, but today there are a plethora of modern tools to add a cold wave to your perm. When your permed hair grows out and the waves start to become looser, you can touch up your hair by applying a cold wave to your perm and curling the newly grown-out hair. The only difference between a cold wave and a modern perm is that a cold wave doesn't use heat to set the curls, which makes it easier to apply this treatment at home.
Wash your hair after ample application of a shampoo. This is to ensure you start the process on clean hair and get the best results.
Using your permed hair as a guide, pin your hair to your curlers or heated rod. Make sure your hair is well-secured around the curlers and that all of your hair is curled in the same direction as the previous perm.
Apply thioglycolic acid lotion -- which is the perm lotion -- to your hair to make it softer and swell to take the shape of the curlers. The lotion will break the protein chains and cross-links of the hair, making it vulnerable to changes.
Wait for 10 minutes. Rinse the hair ensuring that the perm lotion is thoroughly washed away, leaving the hair soft and easy to shape.
Apply the acid neutralizer lotion. Application of this lotion forms the cross-links of the proteins again, which leads to the hair taking on the hard curly shape of the rods or curlers. This lotion will add the cold wave to your newly grown-out hair.
Remove the curlers after six minutes and wash your hair in cool water.