Linseed oil is a flax derivative used to treat wood, either alone or as part of varnishes, paints, and stains. "Boiled" linseed oil is actually something of a misnomer; it is in fact pressed linseed oil to which chemical dryers have been added to speed up the drying process. This is necessary, since straight linseed oil can take up to three days to dry. Once the oil soaks into the wood and dries, it seals and protects the wood against moisture, dirt, and discoloration. There are no tricks to drying boiled linseed oil beyond applying it properly.
Things You'll Need
Boiled linseed oil
Pour some boiled linseed oil onto a cloth.
Rub the oil thoroughly into the wood using the cloth. All the oil must be rubbed into the wood; any excess resting on the surface must be removed by wiping it away with another cloth.
Set the wood piece aside in a dry place for at least 24 hours. It will take boiled linseed oil around this long to dry. There is no way to speed up the drying process beyond applying thinner coats of oil; in such cases, though, several coats may be needed to seal the piece, and each one must dry fully before applying the next.
Repeat the oiling process as necessary until the wood takes on the color and finish you desire. Once the last coat of oil has dried you can buff it to a shine by rubbing it with a dry soft cloth.
Be sure your application cloth is free of lint. Wearing vinyl or latex gloves during application will protect your hands. Leave treated wood to dry where the air is still and relatively dust-free.
Be very careful with any cloths that have been soaked in oil. The heat generated by the drying oil can cause them to spontaneously ignite if piled up together. Set them outside to dry, or place them in a tub of water.