They should be cleaned and left with the drain tiling connections, if any, in good working order.
"The Future of Road-making in America"
Archer Butler Hulbert
The appalling green and vermilion deities who guard the temple courts, indicate fear as the chosen handmaid of faith in this grotesque travesty of religion, but the costly tiling of violet and azure, the rich gilding of the curling eaves terminating in scarlet dragons, and the deeply-chiselled ebony, falling like a veil of thick black lace before the jade and porphyry shrines, prove that even the despised Chinaman offers of his best to the Divinity dimly apprehended by his darkened soul.
"Through the Malay Archipelago"
Emily Richings
To look for footprints on the tiling.
"Alias The Lone Wolf"
Louis Joseph Vance