Ghostly Tokens

I'm running two games using the same maps etc...  Both groups are aware that the other is playing on a different day and I would like to introduce an aspect of the world being an intersection of multiple dimensions.  Is there a way I could leave the inactive game's player tokens on the maps but give them a "ghostly" appearance to add a touch of mystery to the game?

The only way I can think of would be to download the tokens, edit the transparency of the tokens to whatever extent you want, and then reupload them to use for the "ghostly" version.  If your players won't be messing with it all the time, you could make a multisided token with both the normal and transparent versions.  Then you could just flip the image at session start//end.

I have found that a white tint on a token can give an appropriately ghosty effect.

Thanks!  I will try both methods.