Yes, you can wash and condition the loc extensions. The extensions are made with 100%  human hair, therefore the extensions will react to hair product just as your natural hair would. Please be mindful for the first couple of months the loc extensions will internally go through the budding stage just like natural grown starter locs, so for the first couple of months please do not aggressively wash the extensions! Do not pull, tug, yank on extensions while wet, this will  weaken the extensions.