Replace all cells with len()=0 to empty strings

[BNCOXUK]

I made a macro below to replace all cells with len()=0 in the sheet 'ws' to empty strings:

    For Each rcell In ws.UsedRange.Cells
        If Len(rcell.Value) = 0 Then rcell.Value = ""
    Next

I noticed that this macro is very slow as the sheet contains nearly 50k rows. Is there a more efficient way?