Exchanging Hong Kong Dollars in CNY in the mainland

Hello all,

I plan to visit China mainland after I visit Hong Kong & Macau. Well, I am interested about exchanging Hong Kong Dollars in the mainland (Kaiping for example because I plan to travel there immediately after Macau) i.e. what would it be the best procedure to get the most from Hong Kong Dollars when exchanging in CNY in the mainland. Also, is it possible to exchange Macau Patacas in the same way?

Thanks so much