When this occurs, washing with Log Wash alone may not be enough to remove all of the discoloration due to mold growth. We recommend to first use Wood ReNew, along with some scrubbing, in order to remove the visible mold. Once the surface is cleaned with Wood ReNew, use Log Wash to help remove any residual linseed oil.

We don't recommend blasting alone as a method of removing a heavy growth of mold. Linseed oil penetrates into the wood, and although blasting may remove most of the surface discoloration, there may be enough residual linseed oil remaining in the wood to support mold growth under the finish. If the home has been blasted, it will be necessary to give the home a good washing with a two cups of Log Wash per gallon of water solution before applying Prelude.

The best way to prevent this problem is to avoid the use of any product that contains linseed oil. No Perma-Chink Systems finishes contain linseed or other types of organic oils.

For more information, read these technical tips:
Cleaning with Wood ReNew and Log Wash Technical Tip
Why we recommend (and produce) water-based products