This is The Mature Gohan here throwing in my strategy for this very useful card we call Charity. Here is the card.
 
Charity
Attach Charity to your Active Pokémon.  Unless that Pokémon gets knocked out,return Charity to your hand at the end of your turn.  If that Pokémon attacks and does damage to the Defending Pokémon, you may reduce that Damage by any amount (rounded to the nearest 10).
 
Most people will think it can be used just for Mr. Mime but can be used in another different way too. One is for Team Rockets Hitmonchan. Lets say you have a Fossil Magmar up against TR Hitmonchan and you want to smog it and TR Chan did Cross Counter last turn. You have 30 damage and Chan has 40. You can attach Charity to Magmar then use smog to posion it and reduce the damage to zero. If you poision him you wont have to worry about being hurt becuase Cross Counter only does damage dealt from attacks, not effects of attacks.So in result Chan will die...er...faint at the end of their turn if not retreated you no damage will be done to you by Cross Counter. This card I think will be used against TR Hitmonchan more than Mr. Mime I think. It will be useful against him still but I think it will be more effective against Chan. It is best combo'd with Pokemon with Status effects so I wouldn't use it if you Pokemon didn't have any status effect attacks like poision,sleep,smokescreen,etc.It's not for every deck, but if you you have the right Poke's, it will be great.
 
Thanks for reading everyone. Hope you find this advice useful.
 
The Mature Gohan
ssjgohan6@home.com