When's a circle a circle? Tried it out today when I found a small mountain…
Boxes
What if I presented my found circles – I now have a full years harvest – in small translucent boxes? Like the shells and butterflies at Naturalis? This would mimick displaying Natural Artefacts and also make them into a Collection. Then make a pretty cabinet to hold them … Boxes had www.gutter.de on the back, lets have a look at prices. Later: no boxes on their site. Sent them an email.
Later: 300 boxes of visiting- card size are 120 euro. That is ok. Now find boxes of different sizes. Also the foam stuff that holds the pins.