It's not offensive at all! Regardless of how clean your hands look
, they are still riddled with bacteria between hand washings. Everything you touch IE: door handles, keys, a telephone, shopping cart, your face, hair or clothing, and especially money have astronomical amounts of bacteria on them that transfers to your hands.http://environmentalhealthandsafetyo...atio_5324.html
And most people touch their face, mouth, nose and hair without even realizing that they do it.
And most everyone forgets that they handle money, between handwashings, which has been handled by many other people and who knows where they had their hands!!!! Up their nose, scratching their crotch or butt, using the bathroom without washing their hands..... *barf*
When you go to a hospital and visit a person on isolation, regardless of how freshly washed you look, they still make you put on a sterile gown, glove or even just wash your hands.
A person at home gets used to the bacteria in their homes so if they require a sterile procedure for a wound dressing in the hospital, when they are at home they can usually just use a "clean" procedure that is non sterile.
However as people come into your home they introduce "foreign" bacteria that the person's body is not acustomed to, and that can cause the person to get sick or sicker.
You do not need to go into a long medical explanation about the reasons. Just politely asking them to wash their hands so they do not introduce foreign bacteria into your home is adequate enough.
Print out some articles and hand them out to those who feel offended:http://www.ccohs.ca/oshanswers/disea...ing_hands.htmlThe Importance of HandwashingFlu Information
You can also buy some posters to hang near your front door and in your bathroom:http://www.1st-in-handwashing.com/