Remove all values of a key in PostgreSQL hstore How do I delete/remove the value of a postgresql hstore column?

I've got a table named pages and a column named settings - I need to remove the read_only value (basically, set it to empty string or nil).
Something like this, pages is the table, setting is the column, and key is what you are setting to null.

update pages set settings = settings || '"key"=&gt;null'::hstore;