It's hard to say exactly how to do it without knowing what, if anything, is common to the various input strings. For example, if each string has a "Bold" tag (< B >) just before the part you want to keep, the following would do it;
Sub RightTrim()
Range("B1").Select
ActiveCell.FormulaR1C1 = "=RIGHT(RC[-1],LEN(RC[-1])-FIND(""< B >"",RC[-1])-4)"
End Sub
This example simply creates a formula in cell B1 that will put everything to the right of "< B >" in the text that is in cell A1.
Putting the following in cell B1 (with the input in A1) would do the same thing;
=RIGHT(A1,LEN(A1)-FIND("< B >",A1)-4)
FIND("< B >",A1) finds the first character of < B > in whatever is in A1 (so the "-4" is needed so all of "< B >" is removed).
There is plenty more that would be needed (like error handling), but maybe this will get you started.
Jay