I've been reading recently about the practice of discarding of fingernails in a special way, usually by burning or burying. (Sources here)
Please discuss this practice. Any information would be welcome, including:
- Nature of the law--what sort of law is it considered? D'oraisa, d'rabbanan, chumra, minhag, hiddur, what?
- What is the primary halachic and/or philosophical basis for this law? (Already answered in comments)
- Extent of the practice today (which groups emphasize it, and how seriously people take it)
- Evidence that we do, or do not, need to pay attention to it today