Many crystals are fragile and are not water soluble. Please check before soaking them in water.

Run them under cool water and place them outside with sunlight (for at least 30 min) or under the moon (overnight).
Or on a large quartz cluster to cleanse and recharge.
It is time to re-energized when they become dull and clouded.
Alternatively, you can recharge your crystals yourself by holding them in your hand and sending them your own healing energy.
Sea salt is also good for "deep cleansing" and leave it for a couple days.

Some crystals never need cleansing as the are self-cleaning.
Citrine, Kyanite and Azeztulite. So are Clear Quartz and Carnelian and in fact they also cleanse other Crystals.

Smudging (with White Sage) your crystals is also a fuss free way to cleanse and re-energize them.

Or simply just visualize them surrounded by white light cleansing and re-charging them...!!