[VRGRK]

i would recommend you hand wash them.. use a mild dish soap, use a rag not scratchey wool, preforably not sponge either. also make sure yiou rinse them out... clean the cap and inside of the thermus, put the cap back on (while dish soap and water are inside the thermus) and shake it like its a manhatten.. then drain the water, rinse, and let it air dry with the lid not cupped over the thermus... also if you want use a soft cloth and dry the product.