Yes, using Non-member Notes.  These were intended to be a sort of "mini-Tracker" for non-member records only, and many CUs use them for referral notes and details about loan applications for which the non-member applied but was denied.  Check out the related link below for more details on non-member notes in our online help.

If the non-member ever becomes a member, those notes can be automatically copied into a Tracker record.  In order for this to happen, you will need to adjust your configuration by specifying which Tracker and Memo Type you wish to use in Tool #1004 Workflow Controls: Open Mbrships/Accts.  Once the membership is created, the non-member notes will be converted into Tracker conversation on the membership base share (000) account. Otherwise the non-member notes automatically purge if the non-member converts to a member.