residuo

residuo is masculine in Spanish.

residue, remainder; waste, scrap

“Después de eso, dijo, lo pusieron en confinamiento solitario. “Mi cuerpo estuvo ardiendo durante días porque los residuos del gas pimienta seguían en mi cuerpo”.” — After that, he said, he was put in solitary confinement. "My body was burning for days because the residues of the pepper spray was still in my body".

Borrowed from Latin residuum.