Have just discovered this evening that my neighbours cat has been
peeing on a mat in our back hall way (nearest to my front
door...thanks very much!!!!)

We have disposed of the mat but I don't routinely have bleach in the
flat, can I use anything else to help get rid of the smell off the
concrete? It's a small patch about 6 inches across. but I don't know
how long the cat has been peeing there....the mat was soaking!  I've
had a cold and only really noticed the smell at the weekend and
thought it was maybe my cat's litter tray!  How the hell no one else
has noticed (or bothered to do anything about it) is beyond me...as
soon as I opened the front door this evening the stink was
overwhelming and it took me seconds to sniff it out!!!  

Ok, rant over :o)

Any suggestions appreciated.

Lindsey