Seems like Dig has updated his website and I can't find the original article, but I did save a copy a year ago or so. Here's what he had to say about finish removal:
"Before you start the stock, clean out the checkering.
Do this with a brass wire brush and steel wool. Soak the steel wool in surgical spirit and dab onto the checkering. Rub a little then clean gently with the brass brush, following the line of the checkering. Repeat the process until the dirt is all removed. A surprising amount of dirt will come out of the checkering and it will look and feel much sharper. A stock that looks like it needs re-checkering is often just clogged with palm grease and can be refreshed simply in the manner described above. An alternative, perhaps gentler, method is to use a paint stripper such as Polystrippa and a camel-hair paint brush.
Now clean off all the old finish.
Once your checkering is cleaned out, begin to take all the years of grime off your stock by applying surgical spirit to a medium fine grade of wire wool and rubbing back and forth. Soon, a dirty scum will begin to lift from the stock, as it does, wipe it off with the kitchen roll before it sets. Apply more surgical spirit and continue until no more dirt will lift off.
Now allow the stock to dry. Then rub it all over with kitchen roll and then fine wire wool until the wool is not lifting any more dirt. This early preparation will make the papering stage faster and easier, as there will be less to clog the paper in the early stages. If you have left finish and dirt behind it will be clear to you when you start papering, as the paper will get filled up with a shiny wax polish type of sheen very quickly. If that happens, go back to wire wool and surgical spirit or scrape very gently with a new Stanley knife blade. Be sure to remove only dirt, not wood with the blade."
