Spread a tarp on the ground or a work table and place a bucket on top of it. Put on safety glasses and rubber gloves before mixing the thinner and stain because the solution will be thin and splash easily.
Insert a flat head screwdriver until the lid of a can of wood stain and pry it off. Pour all of the wood stain into the bucket.
Open a bottle of paint thinner and fill the empty wood stain can with it until the can is half full. Carefully pour the thinner from the can into the bucket. If desired, you can reduce the thinner to 25 percent by dividing the volume of the wood stain can by four and using that amount of thinner.
Insert a paint stirrer into the bucket and stir the mixture thoroughly for approximately 15 to 20 seconds to combine it well.