How to stop male dog from making his mark in the house.

Question
I have a male Maltese that is 3yrs old.  He is housebroken but when my daughter's male dog visited and made his mark on carpet, furniture and curtains, my dog is now doing the same thing.  How can I stop this??

Answer
You need to thoroughly clean those areas with an enzyme product that will remove ALL traces of urine.

In the meantime, I would keep him crated if he cannot be watched, and basically "retrain" him to remind him of his housebreaking. Neutering him might also help. Another thing that many resort to is "belly bands" since it can be so hard to catch the sneaky little quick leg-lifters in the act. http://designerdoggie.netfirms.com/belly.html