Aluminum pans are available in two weights. Standard weight pans are 18 ga., .040", 1 mm aluminum and heavy-weight pans are 14 ga., .064", 1.5 mm aluminum; heavy-weight pans are 50 percent heavier than standard-weight. Standard-weight pans are usually designated with an "a" as either the prefix or Suffix in the item number and heavy-weight pans are usually designated with an "halogens" as either the prefix or Suffix in the item number. Hand-wash is recommended as aluminum is a soft metal that is attacked by detergents with a high alkaline or acidic nature. Hand-wash with detergents made specifically for aluminum. Through repeated use aluminum will soften and If scoured, will thin.