Cleaning up after puppy 'wee'

Hi, can you tell me what you use if puppy has an accident i.e a poo or wee on the carpet, I have carpet shampoo and flash and other usual household cleaners, but I have been told you shouldn't use anything that has ammonia in it as it smells like wee so they'll go back to the same spot to do it again.
I don't have my own puppy yet, unbelievably but do look after my friends 8 week old and he tends to have lots of accidents at the moment when he comes round and I don;t want it to still smell incase I get a pup and it picks up on it and pees in the same place.
Thanks for your help x

Hi there we use a deoderiser and cleaner in one from the local pet shop. It seems to work well for us. I Have also heard that biological washing liquid diluted works well but test a small area first for colour fastness. Good luck