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Did you install the cssedit plugin aND followed the suggestion above?
Welcome to the community!
If your goal is to absolutely prevent any spam I concur with RJ - your only option is moderation. However, if your goal is either reduce inappropriate content or demonstrate that you do that, there are several plugins that may help you:
And of course on top of these you can write your own plugin - Vanilla is very flexible. There are volunteers on this forum that would help you create a plugin that fits your personal needs.
Note: I only use some of the above mentioned plugins. You may need a combination of these to achieve your goal.
Just a small (and irrelevant to this change) clarification to the comment about the foreign ID - I'd say it's likely a result of an import (e.g. WordPress, feed import, etc.). I happen to work on a new feed import plugin in my little spare time and I also use it...