My 5 year old keeps spitting

My 5 year old once again today spit on another child.  This has happened now 2 days in a row.  It also happened last week.  I have asked him why he did it and he says it's because the other children won't let him play or that it was his turn to talk.  We have talked about how to use our words instead of spitting.  Today, I was very upset that it had happened again.  I have warned him twice that if he did it again that I would wash his mouth out with soap.  Well, today I did as I said and followed through with the soap and put him in his room.  At first it didn't even phase him and then 10 or 15 minutes in the tears started.  He will start kindergarten next year and I'm sure they will not tolerate him spitting at school.  I'm not real sure how many more times my daycare will allow this behavior before they ask us to leave if it doesn't stop.  Please give me some guidance as to what I should do to stop this behavior?

[RockRose]

At that age my son discovered that kneeing other boys in the crotch was very effective at stopping their bullying or other unwanted behaviors.  The kindergarten teacher said you have to hand it to him - he's smart and has found something that works.  The teacher said this wouldn't be tolerated,  though, and that she would monitor interactions better so that he didn't have to resort to racking the other boys as a defense.

I think maybe that's what needs to be done in your son's case.  Instead of making him stop spitting,  work on ways to make him more likable/desired by the other children for playtime, and teach him other ways to get social leverage.  As it is now,  he's found something that works,  and merely taking that away from him will be hard to do if he doesn't have other strategies.

Saying "use your words" is a really effective thing for a mother to say to a tantruming child - because the mother is open to listening to the words.  Other children aren't.  

It sounds like he needs social skills help.