RE: Hand-me-down trainer
There are many things you can use to get the oil out of the balsa. Over the years I've used corn meal and oat meal. Brush or spray on alcohol and cover with corn meal over night. The next day, the oil will be absorbed by the corn meal. You can use just about anything that is absorbant. But first you must dilute the oil that it will leach out of the word.
K2R, the fabric cleaner contains alcohol which permeates the wood, diluting the oil, the powder then absorbs it. Don't use MEK, acetone, or lacquer thinner.
Frank