Usar Split () y Expresion Regular para numeros

[ElPacay]

y porque no has probado esto
dim cadena() as string
dim palabra as string
palabra="factura91/6416565"
cadena=palabra.split("0","1","2","3","4","5","6"," 7","8","9")

asi te deberia reconocer siendo cadena(0) valor que te interesa