How to fix flickering LED flashlight?

So I have gotten 3 or 4 of those LED flashlights you find at places like smoke shops, grocery stores, etc. ranging from $5-$20 each. Every single one of them eventually starts to develop a flicker to them, that usually goes away if I shake the flashlight. Is there anything that can be done to fix this, such as steel wool the inside casing for better grounding, re-soldering parts, etc? I would pull it apart but there is a metal ring preventing me from doing so in the part with the bulbs. Thanks

Did you ever solve this?

I had a problem with a cheap led torch flickering, i tried resolderign all teh joints and cleaning the contacts but it didnt help. I finally solved the issue by soldering a low ohm resistor in series with the leds (between teh switch and the led) ... Problem solved. as far as i know u should always have a resistor when using leds and i noticed my torch didnt have one.