luminium darkens exteriorly due to flames over a period of time but you can rest assured that our aluminium cookware are rust free and lead free and very easy to clean. Here are some instructions to keep your cookware clean. Step 1 take water and boil it. Step 2 mix some salt to the boiling water. Step 3 clean to cookware with this hot water before your first use. Step 4- after cleaning with salf water. Clean the cookware with soapy water. Step 5- after every use you can clean the cookware with soapy water. Step 6- alwats keep the cookware clean and dry for better life. Step 7- never use steel or any metal scrubbers on the exterior of the cookware this will spoil your exthetical look of the cookware. Always only use spong to clean the exterior part of the cookware.