I do not think these are valid form of collateral. Read the full post of the below quote:
What is considered collateral?
These are collectibles. I will take the side of StackItUp here and say that it is valid.
Thank you.
I would estimate both stamps at 7.5 ETH at least. For someone who collects/understands stamps its a valid collateral. i will repay a loan if its get filled. Thanks in advance