It's not reject but I do have a lovely Gold Leaf Team Lotus vinyl sticker, in mint condition with its backing paper still on.
What is reject-material though is a signed photo I have of Karun Chandhok in the HRT at Australia in 2010!
I wish I had more stuff like that, but I suppose the more you have the more devalued it becomes. By only having perhaps one or two 'treasured' items, I think you tend to value them a lot more. I'm not much of a fan of clothing merchandise, mainly because a lot of it looks abysmal and is poorly fitting, but that's why I like my Marussia top so much because it's fitted just right for my lanky skinny body!
The fact that most clothing costs so much money means it's a waste of time in my opinion, I much prefer posters/photos/autograph cards/etc.