We don't recommend it because the chemicals used in these types of products (string friction reducers) can be harmful to the Fretlight polymer fretboard. If you still want to use one of these products we advise the following:

1. Try the product on a small section of the fretboard, for example the 21st fret first to see if there are any adverse results.

2. Cover the fretboard with paper or cloth leaving the strings exposed for the application of the product.