I heard Ibn Az-Zubair delivering a sermon, saying, "Muhammad said, 'Whoever wears silk in this world, shall not wear it in the Hereafter."
Anas was asked whether the Prophet (ﷺ) used a a hair dye or not. He replied, "The Prophet (ﷺ) did not have enough grey hair to dye, (such that) if I wanted to count the fading hairs in his beard (I could have)."