Heat cycling the springs above a certain temperature will change the spring characteristics, as Adrian said. That is fine if that is your intention. Just the act of removing the coatings from the springs will change the spring, this is one of the reasons that Speed Merchant went to non-colored side springs. The new side springs are so much more consistent than the old colored springs were.
Speed Merchant Rev7, Tekin, TQ Racing (wire), Team Tamale
RC Excitement - Buy where you race, support your local tracks.