D'Andrea.. IIRC, they're around P250. I use mineral oil on my rosewood fretboards, since lemon oil is acidic.
That's misleading.
Oil can't be acidic because... it's oil. Of course, oil can go rancid and break down in to fatty acids, but that's another story and doesn't even happen in neither mineral or essential oils. Lemon juice itself is acidic not because of the oil, but because of citric acid.
Lemon oil used for furniture (as well as guitar fretboards) isn't even pure lemon oil, but a mixture of different oils, most (if not all) of which are mineral based.
At the very least, even if a given lemon oil mixture contains a bit of acid, things should be fine provided that the instructions on the label are followed. I've been using this stuff for years and have never had any problems. And even if acidity is a significant problem with unfinished fretboards, the accumulated grime and sweat from our own fingers and palms could probably inflict greater damage.
If anybody wants to save a few bucks (if
properly applied, that 250 peso bottle can last a person with 2-3 guitars at least a few years) and use mineral oil instead, that's cool. There are many ways to go about this and many different tools to be used. I currently have no way of telling which is the best. So, as I implied earlier, the most important thing is to
read the instructions on your product's label!
(Ayun lang, wala yatang directions para sa pag-apply sa fretboard yung Johnson & Johnson, hehehe.)