How to run a seed swap

I went to a seed swap yesterday at a local gardening group and I now know how to run one.
I brought these seeds to swap:

There are two open packets of seeds (radishes and beetroot) from last year and 3 unopened packets I didn't want (courgettes and kale because I had doubles and watercress because I'm allergic to it).
I have no room at all left for vegetables, so I was looking for flower seeds for the front garden:

I was hoping for sweet peas, love in a mist and fennel, and I also scooped some honesty, peach and scarlet nasturtiums, mauve poppies and (presumably yellow) sunflowers, plus some lobelia not in this photo that I've sown already (because I got over-excited and didn't think through what I had room to sow indoors).
So, based on the seed swap I went to, here's how to run one:

1. Advertise the time, place and date of the seed swap locally and/or on the Internet.
2. When people turn up, exchange the seeds they've brought for tokens (these can just be little pieces of paper with something printed on them, e.g. "1 seed swap token 28/2/2015"). Here was the exchange rate they used at the seed swap I went to:

• Unopened packet of seeds (still in date) = 2 tokens
• Opened, part-used packet of seeds (still in date) = 1 token
• Seeds gathered from your own garden within the last 12 months = 1 token
• Out of date seeds = 0 tokens

3. If you are having quite a large seed swap and think you will end up with some leftover seeds (especially if you have someone bringing a lot more seeds than they need, for instance from their garden or leftovers from a previous seed swap), then you can offer to sell tokens too. The price yesterday was 50p per token. 

4. Put all the seeds you've gathered on a table/tables split up into sections based on price. The seeds cost exactly the same as above, i.e.:

Unopened packet of seeds (still in date) = 2 tokens

Opened, part-used packet of seeds (still in date) = 1 token

Seeds gathered from somebody's garden within the last 12 months = 1 token

Out of date seeds = 0 tokens (i.e. free)

5. Have containers for gathering the tokens in each section (e.g. a bowl, a plate or an ice-cream tub). Ideally you should have someone to "sell" the seeds and gather the tokens at each table, but in fact, probably most of it will work on trust and people will simply put the right number of tokens in the container - I think generally gardeners are pretty honest types.

Other tips: I had to wait between handing in my seeds and being able to swap them while the group holding the swap held its AGM. It's probably a good idea to have at least 5 minutes between people handing in their seeds and opening the swap so as many of the seeds as possible are on the table. Also, tell people that the organiser will be keeping any unclaimed seeds. It's then up to you what you do with them, but hopefully you'll find something useful for them (e.g. starting off a later seed swap).