After one uses the bathroom should one wash his hands from a cup? Once or 3 times? Can he wash in the bathroom?
For bathrooms of old, poskim required washing three times ouside the bathroom, to take away the ru’ach ra’ah. Even here, however, there is no need for a cup (see sources in Minchas Yitzchak 5:96).
For today’s bathrooms, the Chazon Ish (17:4) writes that there is a doubt as to whether they retain the same status, and therefore there is room for leniency in washing hands regularly, even inside the bathroom.