What platform do I use to exchange currency on the

I would like to exchange my DOLLARCASH, WORLDCREDIT

TY. is a wallet which allows you to use Counterparty tokens.

As to your question of how to exchange your DOLLARCASH and WORLDCREDIT for XCP or BTC, you can do that on the exchange, but I would first advise you to look at the trade history for these assets and you can pretty clearly see that there is no real demand (buyers) for these assets. A token only really has value if it has liquidity (buyers and sellers) or has some utility, and from what I can see, DOLLARCASH and WORLDCREDIT have neither.