Please help ......

I am still clearing out tidying my craft room and I have found the following in a tin .......... I like tins .......... I have lots of tins............... 
I am trying to reduce them but it is very hard ............. I like tins.

These circle are made of quite rigid plastic. 
I have no idea what this is used for ....... I can only think Pom Poms,

How?
I don't know  ............ but can you think of anything else?  do you know what they are?

I can't throw them out until I know so I guess I will have to put them back in the tin!!!!