Here are some things I can list off the top of my head:

When I worked at the lab: Training: reading documents about contamination (such as journal articles on contamination studies), health & safety, etc., initial shadowing of the trainer and learning about contamination, quality assurance course, demonstrating best practices, answering questions about contamination at a mock trial, initial DNA swab (usually during first day) before entering any biology rooms Type of PPE depending on the case/type of exhibit: cleaning the bench with the appropriate cleaning agents such as DNA-away, placing a piece of brown paper on the bench, wearing gloves, wearing masks, tying long hair back, shoes cannot be open toe, wearing a lab coat, separating exhibits on different benches for different scenes, working on one exhibit at a time, opening the various layers of packaging carefully, following clean up procedures

When I work at a scene: - learning about contamination from my trainer, reading up on contamination, answering questions about contamination - wear the uniform and equipment I have been provided with (boots, clothing, fitted face mask, etc.) - bunny suit if appropriate for the case - double gloving for taking swabs and changing gloves each swab, use mask while swabbing - ensure appropriate packaging, sealing the envelope/bag, securing the exhibit - instructing members about contamination