While it won't have the lyrics playing in perfect time with the music it is possible to strip the vocals from tracks that you can't seem to find on more popular streaming services provided you have an existing WAV file. While it does require a little technical aptitude, it's relatively simple thanks to free tools like Audacity. Simply drop in the file you want, split the stereo track, and use the inverter effect on the bottom track. Once you've done that, select mono playback for both tracks and give it a listen. You will notice some distortion as this is hardly a perfect method, but the vocals will be far less noticeable.