The instant disclosure may provide a coaster that can be used with articles including fluid containers to mitigate and/or preclude undesired transmission of liquids by collecting condensation and dripped fluids and directing them to a contained reservoir within the coaster. An upper flange of the coaster may act as a unidirectional valve, directing fluid into the reservoir and preventing the escape of stored fluid even while the cup on which the coaster is mounted is tilted, as when tilted for drinking purposes. The coaster may be installed and removed with one hand, may move with the cup, and may provide improved cup-on-surface stability.