So much for taking a bar of bath soap.
Why? They had soap and fairly good soap at that.
Soap is not that hard. Basic ingredients, fat and lye from wood ash. Went to the fort at Boonesboro. There was a wooden box about 3 feet cubed. People in the fort brought their wood ash there and water was filtered through it and collected below for soap making. Beeswax makes the best candles, but tallow and lard will get the job done.