What you are seeing is the talc powder used in the manufacture of the bands coming to the colored surface of the latex.
It is normal in time and use for bands, especially if they haven't been used on a regular basis. The whiteish color you are seeing doesn't affect the integrity of the band and is just a cosmetic imperfection.
You can clean this white coating off and recondition the bands with our very own, non-toxic, "Band New" Cleaner/Conditioner.
"Band New" Resistance Bands Cleaner, Conditioner and Restorer is the best way to keep your bands looking their best! Simply apply to the applicator and then apply to the latex. You can let the gel dry or wipe it off with a clean rag. Use "Band New" to keep your bands looking BRAND NEW!
You can order "Band New" here:
"BAND NEW" Resistance Band Cleaner/Conditioner
If your resistance bands haven't been used in a very long time it will be a good idea to inspect the bands very closely for any kind of cracking or splitting in the latex. If you see any cracks or splits  you should not use the bands and contact us for a warranty replacement.