pots for rags
In Lancashire it means someone who either has mental illness or impaired capacity for other reasons. The allusion is to the traditional rag and bone man who collected rags in exchange for small trifles such as a jam jar or a balloon. If you were pots fer rags (pots for rags) you would do the reverse of the common sense expected approach.
Since our Tom got hit on head with that brick he’s been pots for rags!