The acid will remove the 'milky' look that it has. Also, any joints that aren't just right or maybe there is a blob of mortar on a stone....throw the acid to it, scrub/chip and was it off with water. I like the trailer because it is useful. Its a 16' BUT only a 12k GVW......this trailer should be a 14k or even 16k GVW..........12k is pure stupidity. Why? I have a 10ft, 10k GVW dump that allows be to haul 7,500lbs. This 16ft, 12k GVW trailer allows me to haul only 8,300lbs........see what I mean? The dang thing weights 3,700lbs. The ramps are under it for loading and must be pulled out.....heavy and a pain but its useful. The trailer was part of the package when I bought my Bobcat.