Cleaning stone window ledge . . . how?

[TheSalad]

Hi, our windows all have bare stone window ledges/sills to the outside and some have become a bit green and grubby over the years. Don't want to blast them with a pressure washer so was wondering if anyone had any clues as to a more delicate approach to cleaning these?

Hope you can help. View media item 49235

 

[foxhole]

Bleach first to kill the green mold.

 

[PBSCO]

Bleach and then a bit of bi carb and a stiff scrubbing brush will work a treat.