VBA cells merge

Hello to all.
The attached macro deletes in step the column B and the column L.

Sub cancella_tutto()

Dim avviso As String
Dim x As Integer

 avviso = MsgBox("sicuro di cancellare tutto?....", _
 vbExclamation + vbYesNo + vbDefaultButton2, "AVVISO")
      
 If avviso = vbNo Then Exit Sub
 
  ActiveSheet.Unprotect "123456"
 
   For x = 3 To 61 Step 3
    Range("B" & x).ClearContents
Next
  
  For x = 3 To 61 Step 3
    Range("L" & x).ClearContents
Next
 
  ActiveSheet.Protect Password:="123456", Contents:=True, Scenarios:=True, AllowFiltering:=True
 
  Range("L3").Select
  
 End Sub

How can I change here:

For x = 3 To 61 Step 3
Range ( "B" & x) .ClearContents
Next

to delete the column B and C merged?
I hope I explained?
max_max