The CCleaner application features a Duplicate Scanner. This module allows you to search for duplicate files based on file size and file type. To identify the duplicated files without knowing their name, go to Tools > Duplicate Finder, then click on ADD and specify the file type if you know it. Click in the File Types field and add the string as shown in the image (e.g. .tmp;.log). Accept the changes, then go back to the main section of Duplicate Finder and check the partitions where you believe the files are stored.
I also recommend to search by file size. Input the approximate file size of your files.