It may seem that nails, tissues, and money have nothing in common. However, they have something in common with each other. They have a general commonality that they share with millions of other things. This may be why you did not notice what they have in common. They are considered to fall under the category of fomites.
A fomite is a thing that contains germs on it and can transmit viruses to something else because usually they are often used by someone or something and are not cleaned before someone else uses it. Tissues are used and contain many germs because people blow their noses on it. Then it must be moved to the trash can. Many people often handle money.