It doesn't sound like an item is the problem...rather the PCs have more magic than you want to allow as a DM...its done so now have to recover....I suggest a one time application of
Disjunction
Abjuration
Level: Magic 9, Sor/Wiz 9
Components: V
Casting Time: 1 action
Range: Close (25 ft. + 5 ft./2 levels)
Area: All magical effects and magic items within a 30-ft.-radius burst
Duration: Instantaneous
Saving Throw: Will negates (object)
Spell Resistance: No
All magical effects and magic items within the radius of the spell, except for those that the character carries or touches, are disjoined. That is, spells and spell-like effects are separated into their individual components (ending the effect as a dispel magic spell does), and permanent magic items must make successful Will saves or be turned into normal items
This is only a one time fix however.....you control the amount of wealth they encounter and what items they can find or make...determine your comfort level on how much magic is ok with you for PCs to have and then DM.
One final comment, if that sounded harsh...I think every DM has encountered such a situation before, the trick is to see it, recognize it, and either learn to DM it or change how you DM in the future.
I know I have.
Good Luck,
Forsythe