It means cleaning fleas or lice. Eliminate bugs and parasites, especially from hair (hair). Manually remove fleas or lice on pets or nits. .
Sounds like a cross between expurgation and thumb, doesn't it? It's a pity that even though it's used as localism, it doesn't exist in Spanish.
Find and remove fleas on an animal.
This term is used when you start investigating a person to the last