Having read this question: How can one determine the radical for a given character?, it gave me another question.
Since many simplified characters lost their original form (compared to traditional ones), how do I actually look up their radicals? A classical example would be "leaf". In traditional form, it's 葉 whereas it's 叶 in simplified form. The traditional form preserved the 艹 (艸) radical (which means grass), but simplified form does not have it at all. Just by looking at 叶, you'd think it has 口 as radical, but 口 (mouth) has nothing to do with leaf...
If anyone can think of examples similar to this, please share.