Hmmm...
Hard to make sense of what you want. Clear formatting is, perhaps, a
confusing term as all text at all times has _some_ formatting, but what it
does is clear all formatting that's on top of the assigned style. Courier is
a Font, not a style; if you want your text in Courier you must either create
or amend a style to include it and then use that style, or just format your
text as Courier on top of the style. I recommend the style route over the
direct formatting.