Delete other values except "A" and "B" and "C"

I reckon how you have it might be the quickest, the only way I could think of replacing everything except certain characters would be to loop through each character in the string and check it individually, or to use a formula to break the string into an array of characters and use a vba function to concatenate al the A's. B's and C's.

That said, if you are just interested in the length of your code as a character count:

Sub Macro1()
With Sheets("Sheet1").Range("A2:A" & Range("A" & Rows.Count).End(xlUp).Row)
   .replace ">","",xlPart
   .replace "B","",xlPart
   .replace "p","",xlPart
   .replace "t","",xlPart
   .replace " ","",xlPart
End With
End Sub

is perhaps the same?