Вот, что с Dunlop написали:
Interestingly enough, our Lemon Oil is a combination of essential mineral oils and oil from lemon peel. The material, the fretboard and other rosewood /ebony parts on the guitar usually has an ‘open structure’, which is unveiled when the instrument has been in a dry place, or just wasn’t cleaned and maintained. The difference with domestic products is normally the aggressiveness, and the greasiness of the oil (with general products you could end up wiping for hours, and even get greasy fingertips, or just black fingers from the oil. also the smoothness when furniture has a thicker laquer, cause the resonance of the wood is not a feature one needs :-), unless it’s a guitar coach.
... и добавил:
Конфуз в "essential mineral oils". Essential - эфирное, mineral - минеральное (нефтяной дистиллят).
... и добавил:
Опять им написал, чтобы разрешить этот конфуз. Пока молчат.
Писал мне Erjan van der Laan, судя по всему голландец. Может и конфуз из-за этого.
Вообще, странным языком написано, вероятно это не носитель языка писал.