A three-part study was designed to find the safest and most efficient method of processing glassine stamp bags containing suspected heroin while preserving the qualitative properties of the substance. Gravimetric analysis was also conducted to determine whether selected processing methods add weight to clean stamp bags. Qualitatively, the processing methods chosen for this study did not eliminate heroin from the samples. Results of a blind evaluation of developed latent prints indicate that under the controlled conditions of this study, magnetic powdering yielded the most “of value” latent fingerprints. However, because previous research has shown that magnetic powder is most effective a short time after fingerprint deposition (which was the case in this study), this conclusion should be regarded as tentative until longer times between deposition and recovery are studied. Gravimetrically, the processing methods used in this study add an amount of weight to the bags that is within the uncertainty of measurement for this laboratory.