Prevention is better than cure. Take off your tie during diner or throw it over your shoulder.
You should then observe the tie's inside in order to check if it has been made of polyester or silk. A polyester tie can be cleaned easily. A bit of warm water might sometimes already be sufficient. Should this not be the case, you should then add a bit of detergent (without bleach). A silk tie is much harder to clean. There are many fables about it. You should definitely avoid washing your tie with water!
Place the steam iron on position 2, place a tea towel on it and carefully iron it. Don't press too hard and rub carefully over the spot with the stock sticker. In this way you avoid gleaming spots on your tie.
It is not a good idea to wash your tie in the washing machine.