I agree with what Pat, and others have said, and add there is no need to use sand paper or garnet unless you can feel the scratch. Most times when you sand with 150 grit, you then need 250 and 400 to get the scratches out, you left behind. I also agree if it is old wood like Osage, Cedar, or Yew too much sanding creates lighter shades in the wood. I have refinished bows with Birchwood Caseys Tru Oil, and really appreciate how well it rubs out by hand, or with a shotgun cleaning patch. If you buy a small bottle, poke to holes in the foil seal under the cap at 12:00 and 6:00 one for air and one to apply Tru Oil with your hand or cotton patch. When through, put a small bit of kitchen wrap over the top, then hold it while tightening the cap. Otherwise it will become thick as it has a short shelf life. If you need to sand, buy a pack of dark green kitchen fiber cleaning pads. They are roughly 3 x 5 and 1/4" thick. Sand with the grain, lightly and wipe off the dust. It won't leave any scratches. You can us a cotton towel, or T shirt and a little mineral spirits to wipe the bow down before applying the Tru Oil. Mineral spirits is a thinner and clean up for Tru Oil. Work quickly, and after 2 hrs use the pad to dull the finish and apply another coat. Apply three to six coats for a gloss finish. When done, shake the dust out, and rinse the pad. Repeat with light sanding if you want a gloss finish; sand lightly to reduce the gloss finish to a semi gloss or mat finish.
Because you have most of the Tru Oil left and you want to save it, get a spray can of propane and use the extension tube to pray propane under the seal to remove the air.