If you haven't sold items at a jumble before, here's some things to think about. Firstly there are NO rules. Just bring your items along, but them on the table and hey presto. Cleaning and Pricing your items will help you sell more at a better price, but as long as you have a rough idea of the item's worth, that will be sufficient. Relax, chat to fellow stallholders and attendees, sell what you can, maybe buy a couple of items to try them out, but in general think of it as a free day out.