Related על תרומות 8:7

[Wine in a container attached to] a strainer is forbidden due to exposure. [But] Rabbi Nechemiah says, if [the portion of the container topped by a strainer] was underneath, it is [considered] covered, even though the upper part was exposed. Behold, [the wine within] is permitted because a snake's venom is like a sponge, and it stays in its place.