Quick Purification
1st, get the colgone case(Agate village-after 4th person in cave). Then buy some scents from the Pokemon market( I would suggest Excite Scent). Give them to your shadow pokemon. Their Shadow Bar will go down. Then, take it to the Relic Stone or the Purifying Chamber. It will be normal.
More tricks, tips and cheats for this game are right here - Pokemon XD: Gale of Darkness cheats
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