DIAGNOSIS: Product buildup and wrapped hair on the nylon and ionix bristles is normal, but it reduces performance and can smell burnt when heated.
FIX: Unplug the dryer and let it cool completely. Use a fine-tooth comb or a seam ripper to carefully lift and remove the hair wrapped around the base of the bristles. For product residue, dampen a cloth with a little rubbing alcohol or mild soapy water and wipe each bristle clean. Avoid getting liquid near the barrel seams or air intakes.
IF THAT DIDN'T WORK: For stubborn, baked-on residue, some people carefully use a soft-bristled brush (like a clean toothbrush) with a bit of isopropyl alcohol. Be gentle to avoid snapping the bristles.
HEADS UP: Never submerge the dryer or run water directly over the bristle head. Clean the bristles weekly if you use a lot of product. Built-up gunk can eventually melt onto the heating element and cause a burning smell or smoke.