مختصر صحيح بخاري
Mukhtasar Sahih Bukhari
Book of Food Laws
Licking and sucking fingers before wiping them.
Narrated Jabir bin Abdullah (may Allah be pleased with him): In the time of the Prophet (peace and blessings of Allah be upon him), we did not have napkins (to clean our hands after eating). Our palms were all we had. (We would wipe them on) our arms, feet, etc. (We would rub them and then perform prayer, without performing ablution again.)