Foam rollers and rolling balls such as lacrosse ball got very popular in last few years. I can hit most muscle groups fairly well with a roller and a lacrosse ball but I have lots of difficulty working on my biceps and forearms. For these areas you I use a barbell.
If you lay down and just roll a barbell on your forearm you will notice how effective this is. I do this with my palm up and down. This is brutally effective and same concept can be used for the biceps. Check out videos below for how to do it. Please note that you can use the handle of the barbell or the end of the barbell. This way you can easily increase the weight by moving toward the center of the barbell. Happy Smashing!