sand it
use paint thinner or white spirits
Timber Frames can be finished with any wood stain or urethane.
Water! power wash it. You can rent a power washer and do it yourself. If ther is a lot to be done then hire someone who can help.
1) varnish 2) use a wood stain
Yes you can clean the timber as well as possible an restain it.
The stain could be caused by mold. The wood should be pressure washed and treated with a sealer. Another type of black stain in timber is caused by iron oxide. When the moisture in the timber has caused the iron in any fixings, such as nails, to rust and form ferric oxide. This is black, and this travels through the moisture in the timber causing patches of black staining.
Sanding them off is the only way. You may have to sand the entire length of the timber in question to preserve the look, when you repaint or stain it.
Yes, mineral spirits can effectively remove wood stain.
You are probably not going to remove the "stain" from the cover. It has been bleached of all pigment.
There really isn't a way to remove a paint thinner stain from wood furniture. You must repaint or re-stain the furniture.
To remove a Pentel pen stain from clothes, you can try rubbing alcohol or a stain remover directly on the affected area. Gently blot the stain with a clean cloth until it starts to lift, then wash the garment as usual. It may take a few tries to completely remove the stain.
A PVC cleaner will remove oil deck stain from the vinyl part of a window. Pour the cleaner on a clean sponge or rag and wipe in the direction of the grain to remove the stain.