For one thing, don’t paste directly from Word or the like. Results are usually bad, and in one case I saw, proprietary Word code completely screwed up a site.
Tiny editor does have a couple buttons you can try “Paste from Word” and “Paste as Plain Text”. You could try them. If you’re trying to maintain bulleted lists and stuff like that, the first one may possibly help.
But at times I only get reliable results by copying crud from Word into my text editor, which strips out all bad style, HTML, and Word code and leaves me with actual clean text.
