Dm Mon

[kuulteach]

29a class deal poorly with so-called skin condition ?o?n?l?e?n?e

[elliemay1]

formaldehyde?

[Helewel]

Formaldehyde is correct

[MargoTester]

Formaldehyde

[fiction-factory]

that would be good if clue said preservative or similar

[Captain2]

Class deal poorly with so-called skin preservative (12)

Full clue

[kuulteach]

thanks

[fiction-factory]

class = form
deal poorly= alde
so-called skin = hyde (sounds like hide)
then last word which is preservative (or could have been chemical or similar) is the definition