Evaporation

Can anyone tell me what is the best stuff to make the little rectangular wafers that wick up the water and help evaporate it. To be more descriptive, there is a tube runnibg from the floor of the refrigerated area down to a tray/tub with holders for some kind of wafer to soak up water. Any ideas?

[johnieG]

Checkout your local hardware store or heating and cooling supplier! the pad's use by furnace evaporative humidifiers are very simular '>  and you could cut them down to fit.