Fathwa, - Is it permissible to use the nail whitener pencil?

Question:
Is it permissible to use a nail whitener pencil on the inside bit of
the nail to make the tips of the nails look whiter?
Answer:
In the name of Allah, Most Gracious, Most Merciful
It seems as if most pencil whiteners leave a barrier such that one''s
ablution is not valid if made after using it.
Note that it is reprehensible to let the nails grow long (Al-Durr
al-Mukhtar 5:260) even if it is done for one''s husband.
And Allah Most High knows best.