Sounds like it might be oral thrush. Go to your local chemist and ask the pharmacist to take a look - she can get you some canisten or similar if it is.
It'll just be random phlegm and stuff - I get it whenever I have a cold. Best bets are quite literally scrape it off as someone said above, use mouthwash or rinse your mouth out with hot water. Brushing your teeth isn't gonna help unfortunately.