Given the preoccupation of many today with buying the softest possible toilet tissue, it's a little bizarre to note what was used for the purpose in ancient Greece and Rome. The British Medical Journal reports:
During the Greco-Roman period, a sponge fixed to a stick (tersorium) was used to clean the buttocks after defecation; the sponge was then replaced in a bucket filled with salt water or vinegar water. Another technique was to use oval or circular fragments of ceramic known as “pessoi” (meaning pebbles), a term also used to denote an ancient board game.
. . .
Many pessoi have been found within the faecal filling of Greek and Roman latrines all around the Mediterranean world. Pessoi found during the American excavation on the Athens agora, for example, are described as 3-10.5cm [about 1.2"-4.1"] in diameter and 0.6-2.2cm [0.25"-0.87"] thick and having been re-cut from old broken ceramics to give smooth angles that would minimise anal trauma.
. . .
Some scholars suggest that ostraka, small pieces of broken ceramic inscribed with names that the Greeks used to vote to ostracise their enemies, could also have been used as pessoi, literally putting faecal matter on the name of hated individuals. (Examples of ostraka with the names of Socrates, Themisthocles, and Pericles have been found in Athens and Piraeus).
There's more at the link, along with photographs for those visually inclined.
Obviously, the ancients hadn't been to Charm(in) school . . .