Cleaning up old files

[JUNIPER]

GnuCash 1.8.11 Red Hat 3
I use "allfinance" as my basic working file and keep it in a GnuCash 
directory (as well as occasionally to a flash card). .xac & .log files 
keep accumulating. Shouldn't they be automatically deleted or replaced 
after a certain amount of time? There are now 152 files there. Is the 
only option for me to periodically manually delete all of the .xac and 
.log files (hoping I don't accidently delete "allfinance" as well!  Is 
it possible to not make those files at all? (back up with sufficient 
frequency that I don't feel I need them)
Steve J