Board Thread:Speculation House/@comment-27121579-20160104011025/@comment-4010415-20160105121329

Regardless, I'm pretty certain that, when Cinder's clothes glow, she's using Dust.

Mind you, there have been at least two times where she has used fire powers without her clothes glowing. Once was in the Volume 1 after credits scene, where she conjured fire in her hand and her eyes were glowing, but her dress was not glowing. Another time was when she made a popcorn kernel pop, at the end of Round One.