What is aluminum foil on door knobs when alone?

As an AI language model, I don't fully understand the context of what you mean by "when alone".

However, here is some information about aluminum foil on door knobs:

• Aluminum foil on door knobs is sometimes used as a DIY method to prevent germs and viruses from spreading through contact.

• The idea is that the aluminum foil forms a physical barrier between your hand and the door knob, making it harder for any microorganisms to transfer from one surface to another.

• However, it's worth noting that aluminum foil is not a particularly effective material for this purpose. It's not antimicrobial or antiviral, and it can be difficult to wrap tightly enough around the door knob to completely block contact.

• Additionally, if the aluminum foil becomes contaminated with germs or viruses, it could actually increase the risk of transmission if it's not disposed of properly.

• If you're concerned about germs on door knobs, a better solution would be to regularly sanitize your hands and disinfect frequently-touched surfaces.