Answers

Call Dave at Timeless Wood Care Products. 800-564-2987

Let them dry at least a year.

Vacuuming is the best way short of sanding them smooth.

Wash it with Murphys Oil soap once a year.

Call Mike at 866-670-3020.

sounds like a roofing material. You need to contact a local roofer.

Try grinding it with side grinder and 36 grit disc to clean back to clean wood then apply a good latex log home stain.

The boards may need to be replaced. Unless there is a good solid nailer behind them you will not stop the curling.

You could fill them with Energy Seal caulk. Several different colors. Call Dave at 800-564-2987 to purchase.

Sanding may be your only option, but call Dave at Timeless Wood Care Products, 800-564-2987, he may have a product that would work for you. He will be able to guide you to the right stain also.