List of Clients in Credit

Is it possible to get a list of clients who are in Credit?  We have a lot of clients who pay in advance and I cannot find a way to see who they are unless I go into the statements and include them in the list of debtors.  You can "include clients with credits only" but you cannot get a list of of  the "clients in credit Only". As you cannot export the summary of debtos and creditors to excel so I can sort it, it takes me ages to trawl through the list and separate them out. This would be very handy for us.  Thank you