The previous owner apparantly didn't realise that powdered lime, when commonly wetted by moisture, becomes hydrated lime, which is an alkaline solution that etches aluminum. Muriatic acid is a weaker version of hydrochloric acid, which will clean lime deposits. Unfortunately it is very strong when used around aluminum, and has a strong odor which necessitates the use of a chemical respirator in any inclosed space. It is a definate health hazzard to use, especially in large volumes. Muriatic acid is now available with a less smelly formula, but still should be a concern when used within inclosed areas. It may take several applications to break the lime free from the flooring, but it is probably the best way to clean the floor and treat any present corrosion. There are mechanical means to abrade and clean the flooring, but with an active acid coating, not creating a spray or mist becomes a problem. A random orbit sander with a coarse non woven pad, cleans very well. A drill chucked with a brass brush wheel, normally polishes aluminum without destroying the base metal. You might try the acid wash a few times to see how effective it is. Use an especially stiff roofing brush to agitate the acid onto the flooring. Let the acid then sit for at least 15 minutes or until you see no further chemical reaction. Well rinse the floor and examine the results. Anything remaining can then be safetly abraded without spreading the acid. The flooring will then be ready for a coating, whether it is a single part cold applied DIY bed liner, or a two part commercial hot application. Never use lime around aluminum. With a liner applied, your only maintenance will be occassionaly to roll the mats and flush out the pax (butt) side. Normally you will not have to completely pull the mats again. | 
Alum Floor/Muriatic Acid
