Magic is also a simple subject when broken down. You have three things: a medium, the mana pool in your body, and your veins. Magic muteness is caused by a blockage of magic in your veins, so if you could create a spark large enough to cause an explosion, that means you cleared your veins enough to allow magic to flow through. However, the process can take years of casting magic sparks before even casting a spell. Sometimes, it is in a matter of minutes, depending on skill, yet that only clears it for a short time, not wholly erasing the condition. 