Unwanted certificates?

Searching for the birth and death details of one of my ancestor's children has been a slightly frustrating 'brick wall' for me, and recently I was excited when I thought I had narrowed down the child to maybe one of 5 possible children. I felt the only way I could make sure was to send off for the death certificates, and so last week that is what I did. To my disappointment none of the certificates were from my family and so now I have documents I don't actually need. I was sad to see that it appears I now have certificates from a set of twins, one dying on the 25th February 2011 and one on the 27th January 2011. Same mother and father, same father's job, same address, same age of 14 months, both measles as reason for death. It has been rather sad to look at the death certificates of those children and brought it home to me, yet again, what life must have been like 100 years ago, in Poplar, London.

Anyway, I am sure other people must have unwanted certificates and wondered if there is a recommended site to post the details of my documents? I have used one I found for now, but to be honest I know there are quite a few sites around and wasn't sure which was the best? I cant see anything like this on Lost Cousins, but that could be because I am not looking properly!