Character Formats showing up in TOC
TOC entries for, say, "Heading4", are nominally controlled by the paragraph format of the generated "Heading4TOC" format.
Sometimes the body narrative will have local mods to the Heading4 text. Depending on what you're doing, you may want those mods to show up in the TOC, or you may not. In my case, I did not, and was surprised to see a TOC entry show up in color.
It turns out that if you apply a Character Format to text used for TOC (and perhaps IX, LOF etc) generation, that ChrFmt is retained when rendering the TOC.
So if you want the local enhancement to appear in the TOC, use Chr Fmt. I verified this by setting a heading word to Character Format "Symbol" (which applies the Symbol font`, all else As-Is). The TOC entry had that word in Symbol glyphs.
if you don't want the local enhancement to appear in the TOC, use local overrides. I verified this by just doing a Format > Font > Symbol on the same word of the heading. The TOC entry had that word in roman.
_______
In my case, I have a table imported (as EPS) from a spreadsheet. I want the table title to appear in TOC, but of course Frame can't "see" that text. So the anchor line is that title in Heading4, which does appear in TOC. This particularly H4 has a local color override that is set invisible via Color Views. I want the TOC entry to be visible, but the Heading4 text in the body to be invisible. This works if the Heading4 has the invisible color applied with the graphics tools. It doesn't work if I use an invisible text Character Format.
Another way to hack this particular problem is to put the Heading4 title in a text frame behind the imported image. Then it requires no character formatting magic. But you can't see it during edit, and you need to hope that the table white fills really are, and aren't just transparent.

