You're getting intermittent issues with your device, so you suspect there's contamination in the electrical contacts. Dust, dirt, grease, and oxidation contamination can increase electrical resistance in contact
Some people may lavish money and attention on home security, but then cut corners when hiring a house cleaner. It’s a bad decision that could cost more than you imagine. The workers who enter your private domain should not only be skilled at their jobs, but vetted and backed up