Cleaning bricks are described as made from fiber-reinforced plastic, while pumice-style blocks are made from natural pumice material.
Grill cleaning bricks are intended for flat or hot grill tops and baked-on residue; pumice heads are shown for toilets, sinks, bathtubs, and tile surfaces.
These scrubbers have a temperature-responsive core: they firm up in cold water for tougher scrubbing and soften in warm water for gentler cleaning.
Some bricks are sold to pair with compatible handles for easier use, and certain pumice refill heads are described as compatible with common toilet-wand refill systems.