Mineral oil and linseed oil are commonly used in instrument fretboard oils. Each oil has advantages and disadvantages, but both are effective in accomplishing the task. As a matter of preference, some individuals lean towards linseed oil-based finishes because they are free from petroleum. We recommend linseed oil-based finishes as they do not contain petroleum. However, ultimately, the choice of oil for your guitar's fretboard depends on personal preference and opinion.