clean has different interpretations, for me clean armor is no brittle no antique but clean jewels could mean if legendary its not antique but clean lesser jewels means that its not antique or also that it has no mods that shoulnd be there like: if you, for example, want to imbue a 10ssi jewel with 25 ep 15hci 15dci 10ssi and 25di, clean, for me would me either it is not antique or that has a mod that bothers the other 4 mods like 4 dex or 4 str or 4 int or 4 mana or 4 stam. So its not really "clear" what "clean" means in lesser jewels like 10ssi ones. Hope i Helped you understand. But u need to know the mods that would fit in the lesser jewel in a properly imbued way to know what should NOT be there, u get me?
Regards,