Hoʻokō nā pōpō kila kila i nā koi no ka pōleʻa paʻa ʻole me ka paʻakikī maikaʻi loa a me ke kūpaʻa ʻana i ka corrosion. Hiki ke hoʻonui ʻia ka pale ʻana i ka corrosion ma o ka annealing. Hoʻohana nui ʻia nā pōpō non-annealed a me annealed i nā valves a me nā mea pili.