Abū Hurairah Radi Allāhu ‘anhu narrates that there was a black gentleman or black girl (a narrator had question as as to if it had been a male or woman) who used to sweep the Masjid. She/he passed away. Nabi Sallallāhu ‘alaihi wa Sallam requested (his companions) regarding this individual, https://one-bookmark.com/story18610388/how-to-clean-mosques-things-to-know-before-you-buy