Some dryers can leave brown stains on clothes due to the clothes rubbing across or getting caught in loose felt drum seals. Use a white cloth or rag to rub the inside perimeter of the dryer drum at the front and back to see if you get brown marks on the cloth or rag. If you do, then you may need to replace the felt drum seals.
On some dryers, a problem with exhaust air flow could cause overheating of garments. Make sure that the lint screen is clean before every cycle. If you use dryer softener sheets, then I recommend periodically washing the lint screen with water and a nylon brush. Check the flexible exhaust vent behind the dryer for kinks or clogs. Check the exhaust vent duct to the outside of the home for clogs or restrictions. You may need to have a duct cleaning service clear your vent ducts.
These tips may help you resolve this problem. If you need more help, resubmit your question with additional details and the full model number of your dryer.