Having seen kayakamina's answers at 10.21 and 8.23 to 9a = iodine, and 28a = misnomer, could he or someone please explain how the cryptic clue fits the answer.
To me, "I use it perhaps" would indicate an anagram, and I can see no connection between "misnomer" (apart from it being latin - does that mean public school?) and the clue.