When I was in basic training in the Army, we did a one week bivouac in the back country of Fort McClellan, Alabama living out of small two person tents. Cleaning yourself meant dipping your steel pot (helmet) into a 55 gallon drum of cold water and washing yourself with that water, a rag, a bar of soap, and a towel two sizes too small.
Going for a week without a bath or shower is something that I never want to experience ever again. Nowadays, the longest I have ever gone without bathing and will ever go without is 2 days, if that.