Why is Lucifer portrayed with dirty feet?

From TVTropes:

Does Not Like Shoes: Lucifer, who is otherwise well-coiffed. Word of God states that the reason Stormare's feet are dripping with goo is that he must pollute the ground to walk on it. Neither does Gabriel when she(?) isn't wearing a suit, which implies this is a standard angelic trait.

Note that I have not found any relevant Bible texts to support this claim.

According to Peter Stormare:

But I said, “My experience from stage is, if you do a devil or a really, really mean guy onstage, you usually come in like in Chekhov, off-white linens suit. My suggestion would be an off-white linen suit. I should come from a bog, not from underneath, and I should have tar on my feet dripping down. And then I can shave away my eyebrows, I can shave my head—you know, the sides of my head—looks weird, and the makeup artist added some veins on my face.” And I said, “If I’m dressed like that, everybody’s going to listen to me. They’re not going to be disturbed by, ‘He looks too fat. Wow. Fit? No, there’s a little belly. The tattoos are moving—they are cool.’ I could say whatever then. I could donate every single sentence to the starving people of Somalia. No one would hear.”