Simplify the following text for a Grade 6 native English-speaking person.
Original: It may be accomplished by using hair irons and hot combs , chemical relaxers , Japanese hair straightening , or Brazilian hair straightening . In addition , some shampoos , and conditioners and hair gels can help to make hair temporarily straight .
Simplified: Permanent hair straightening keeps the hair straight for up to a few months , even when the hair gets wet .