Containers are processed according to E.P.A. recommended wash procedures - Washed with laboratory-grade biodegradable, non-phosphate detergent; Rinsed with ASTM Type I De-ionized water; Oven dried; and Assembled in a contaminate-free environment. The exterior of each case is labeled with a lot number. Each case contains a "Certificate of Analysis". An independent laboratory is used to certify the container's cleanliness, assuring impartial results.