You can install VLC Media Player in the Software application, then:
You might have to get creative here. It's known that if you burn the music files to CD, then rip the files, it'll eliminate the DRM.
But what if you don't have a CD burner, or don't want to burn a bunch of CDs?
Then set up a 'virtual CD' (a file posing as a CD drive), burn to it, then rip from it.
Create a block device by creating a partition: dd if=/dev/zero of=file.img count=102400
... or whatever size you want for 'count'... then mount it as a loopback device: losetup /dev/loopX file.img
... where 'X' is a number.
Or create a ramdisk: mkfs -q /dev/ram1 867328 (847 MB, the maximum size of a CD... or whatever size you want) mkdir -p /ramcache mount /dev/ram1 /ramcache df -H | grep ramcache
Format the ramdrive as FAT32. It'll show up as /dev/ram1. Then burn to that as though it were a CD, then rip from it.
I believe the DRM parameters are saved in the file metadata, so one old trick we used to use to strip metadata out of photographs was to save it to a FAT-formatted drive. Back in the day, FAT didn't support metadata, so that information was lost when it was saved to a FAT drive. I'm not sure if that's still the case, though.
But there would be at least 1 way to do it. I searched convert DRM protected WMA files to mp3 online tool on Google and there were many results, but I don't know which way to choose, I never used audio and video files often.
Don't know what the results would be but you could play your material in your preferred player after starting a screen recorder of your choice to capture the material and then alter file format afterwards?
That's another great idea, @Tecratonic, in case you're tired of finding a way to do what you want and looks nothing else works you can do as swarfendor437 suggested, why the hell I didn't remember this ?