Radiation sponge
From Tardis Wiki, the free Doctor Who reference
The Radiation Sponge was a sponge-like, alien object owned by Torchwood Three. Though it looked like a normal loofah, it was capable of absorbing six types of radiation and was so effective it needed to be kept in a lead-lined case. When Owen Harper was accidentally irradiated, he was quarantined and forced to carry around the radiation sponge for a day. (TWN: Another Life)
