What is the origin of the idiom "look like something the cat brings in" and when to use it?

The origin of this phrase is not entirely clear, but it is believed to have emerged in the UK in the 19th century. At that time, it was common for domestic cats to bring in small animals they had caught as gifts for their owners, often leaving the dead or injured creatures on the doorstep. This behavior may have led to the association of cats with unclean or unpleasant things, which in turn led to be used in a humorous or teasing way of a person who looks dirty or disheveled.