Q. If there is a sponge or a rag lying in the sink, is one permitted to turn on the water on Shabbos, or would this be considered “laundering” the sponge (since it will become soaked with water)?

If this is, indeed, a problem, then what should one do if he needs to wash for bread, etc., and there is no other sink available?

A. Poskim (Pri Megodim – Eshel avrohom 320: 22 et. al.) maintain that a wet sponge is muktza since it is a “keli shemelachto leisur” or a utensil designated for a prohibited purpose on Shabbos. Therefore it can be removed “letzorech mekomo” or if you need the space it occupies. If the sponge is dry, Biur Halacha (320: 17) quotes different opinions and remains in doubt. Some Poskim permit its removal when in need (39 Melochos 2: p. 354)
Horav Shlomo Miller’s Shlit”a opinion is that you should not pour any water on it as it could be sheriya or washing, but you should remove it indirectly by using a hanger or a fork, being cautious not to squeeze out any liquid from it.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a.