Well Ideally you want to stop the creation of the unp99999999.mdmp files to avast as I believe these are error conditions (and probably why they remain), which it would be better to fix the problem than the symptom.
I don't have any of the logging9999999999.log files in my Log sub-folder (image1), so I don't know if you have something like debug logging enabled, are these files created daily ?
You could also restrict the size of these user log files in the avastUI, Settings, Maintenance section (image2) I have mine set to 32KB and that may account for the multiple Mail9999999.log files.
I don't have CCleaner clean any avast area.