Those who have killed bad people know that common methods to eliminate traces of crime include:

1. Fingerprints: Dissolving oils with medical alcohol to thoroughly destroy them, making them unidentifiable in literature.
2. Bloodstains: Using anionic cleaners to degrade blood proteins, destroying DNA and the original shape of blood traces.
3. Footprints: Applying cleaning solvents to destroy footprint features, causing trace cells to fall off.
4. Saliva stains: Absorbing and air-drying saliva with fiber tissues, greatly enhancing DNA extraction efficiency.
5. Fibers: Using adhesive products to cause fibers to detach, losing original microscopic clues.
6. Palm prints: Covering with talcum powder to fill in and blur ridge lines, making palm print identification impossible.
7. Tool marks: Chemically corroding contact marks with rust remover, damaging force contact features.
8. Hair: Using static dusters to electrostatically attract hair, causing displacement and loss of original position.
9. Contact traces: Wiping with disinfectant wipes to erase traces, degrading biological samples and micro evidence.
10. Bullet marks: Rinsing with high-pressure water to destroy scar patterns, eliminating residual shooting evidence.
Disclaimer: The above content is from criminal investigation novels. Do not take it seriously; if you do, just take it seriously.