Black spots on larch how to remove

[houstonwehaveaproblem]

I have just fitted some larch cladding and noticed some black spotting/mould appearing in places.

Can anyone advise of a good product to remove it before I put a coat of oil on.

thanks

 

[blup]

Sand it off and re-stain, but if it's because of dampness in wood it may reappear.

Blup

 

[Maryas]

Osmo power Gel worked on my oak door. No need for sanding and as its a gel it sticks to vertical surfaces.