Oyeretsa mafakitale ndi mtundu wa zida zoyeretsa omwe amagwiritsidwa ntchito pochita ndi mpweya wa fume, zida ndizochepa kwambiri kukula, zopereka zopereka zili mpaka 95% kapena kupitilira apo. Dongosolo la ku fayilo limagwiritsa ntchito magawo anayi a kuyeretsa, kusefa zosanjikiza ndi kusanjikiza kuti utsi woyipawo umatsukidwa bwino.
