Summation of unique no. in a Spreadsheet range

VBA code for summation of unique no.s in an excel spreadsheet range:


Function uniquesum(Rg As range)
    Dim rng As range
    Dim ccell As New Collection
    Dim var As Variant
    On Error Resume Next
For Each rng In Rg
ccell.add rng.Value, CStr(rng.Value)
Next rng
For Each var In ccell
uniquesum = var + uniquesum
Next var
End Function