Found on the Folly - Assortment of "Oxidised" Objects

 I've found these, some I can identify but the other's are mysteries.  Maybe someone can tell me what they are.

1.  2 round objects - identified as wheels from a vintage Oldsmobile plastic car

2.  Stick of Graphite I think

3.  Horseshoe, circa unknown

4.  Unidentified round object

5.  Top of a sardine tin

6.  Round flat disk, unidentified

7.  Brass door poull?

8.  Unidentified round object

9.  Half a jar lid

10.  Unidentified round rusted thingy-me-bob

11.  Filing cabinet marker?

12.  Looks like a chess piece or an ornate gate decoration

13.  Little spoked wheel of a toy cannon

14.  iron ore (slag) or leftover welding blob?

15.  Old door latch

16.  above little wheel, unidentified piece of metal

17.  This is the most interesting unidentified object,  I have no idea.  Mrs Acton says, maybe a hook for handing up something like a lantern

18.  Unidentified round object

19.  Top of a vintage cold drink tin

20.  Object above brass knocker.  It might be an old battery ( this is why we should not throw batteries         in the trash, we should take them to be disposed of safely)

21.  The biggest rusted object, the side mirror of a car.  Which one, I don't know!

If you know what any of these are, please let me know