Product review (1 stars): Honeywell HMP-12P QuickSteam Mineral Absorption Pad
The pads don't seem to do much.  With or without them, calcium deposits gather on the metal plate they're supposed to protect at about the same rate.  I use them only because the manufacturer says to and I need to break the bad habit of being a rule-follower.  It seems to me the best remedy would be to just pour a little vinegar/water solution onto the area and let it soak--but I haven't had the guts to try it yet.  The warranty is supposedly void when you use any chemicals not recommended by the manufacturer.  I'll let you know how it works when the warranty runs out.  In the mean time, don't waste your money.