Preparations

"Some people have a few advance preparations. One is to collect a supply of untraceable paper. This means going to an office supply store and buying a ream of package. This comes in a sealed package. Some people handle it without leaving fingerprints. Some people obtain several pairs of surgical globes. Some people feel there's no point in taking a chance when precautions are so simple and easy. Today, computers make it easier than ever to match fingerprints. The Automated Fingerprint Identification System (AIFS) stores millions of digitalized fingerprints and running a match takes less than a minute in most cases. It used to be that manually matching fingerprints by magnifying glass was so time-consuming that police didn't even try to do so except in major cases, and then only if they had a short list of suspects. Today, a fingerprint found at a crime scene or on a questioned document can be developed, digtized, and run for matches against millions of other fingerprints in minutes.Normally, policewill try to match fingerprints with their crime fingerprint files, but it can expected they can begin running matches on everyone who was ever fingerprinted, because it's so quick and easy. Therefore, if a person has ever been fingerprinted in the armed forces, on the job, in a hospital, orphanage, or almost anywhere else, the digitized prints may be in a computer somewhere, waiting to betray the person. Some companies fingerprint all employees. Another way to avoid leaving fingerprints is to coat the fingertips with a light film of Duco Cement or airplane glue. This coating is much less conspicuous than wearing gloves, and it peels off without leaving too much trouble afterward. Think of how a person would look wearing rubber gloves at a newsstand or in a library. This won't prevent a person from leaving palm prints, but these are very hard to match, and being careful will avoid this danger, as well. A person could paint their palms with a protective coating, as it's not too hard too remove.
It's even more unlikely that any law enforcement agency will try to trace a person via DNA samples in the saliva, but a person can forestall this remote possibility by using self-adhesive stamps. Like wise, a person may not lick envelopes to seal. A person could use a wet sponge instead." This is what Victor said.