Yes You Can
If your having the inside of the guttering cleaned and the outside has gone a bit green why not get the outside cleaned as well. As you can see from the above photo it can make a huge difference to the appearance of your house.
Costs are usually the same again as cleaning the inside. For example 3 bedroom semi detached house would be £65.00 for the inside of the gutter and if you wanted the outside cleaned as well another £65.00 ,so £130.00 in total.
Cleaning is done with a water fed pole much the same way as we clean windows.
Kingfisher Gutters, 5 Pine Walk, Northchurch, Hertfordshire. HP4 3YZ