CloneSpy is a tool that can help you find these files and delete them from your system, freeing up some space in your memory at the same time.
The program works by searching for coincidences in the name, date, and time, making sure that the two files are actually clones. It can also finds files that, without being identical, have the same name or similar size (which you might get confused), and files with 0Kb in size that don't have any content at all.
CloneSpy can delete these files, or move them to any specific folder, automatically or asking you first. All of this comes in a useful interface that includes several search windows.