An alternative way to eliminate dysfunctional large veins with thermal ablation is so-called mechanochemical ablation (Clarivein). In this technique a small fiber is inserted into the vein under local anesthetic. Its tip rapidly spins while releasing a sclerotherapy drug to the vein. There is no heat required. The technique appears to act by scratching the inner layer of the target vein whilst allowing the sclerosant drug to create a reaction that eventually seals the vein.