Dual Guitar String and Fretboard Cleaner Maintenance Care for Guitar/Bass/Mandolin/Ukulele (Yellow): Amazon.co.uk: Musical Instruments
How to Clean a Guitar Fretboard - Procedure for Really Dirty Fretboards
Is lemon Oil Safe for Cleaning My Guitar Fretboard? - Tone Topics - Dedicated guitar site with everything guitar gear, how-to guides, tutorials, reviews for all guitar players.