Nakuba insimbi engagqwali yaziwa ngokumelana nokugqwala, ayivikelekile ngokuphelele ekugqwaleni.Kunezizathu eziningana zokuthi kungani insimbi engagqwali isengakwazi ukugqwala.Okokuqala, ukungcoliswa kwendawo njengokungcola, uthuli namakhemikhali kungalimaza ungqimba lwe-oxide evikelayo futhi kuveze insimbi ekugqwaleni.Kubalulekile ukuhlanza njalo izindawo zensimbi engagqwali ukuze ususe ukungcola okungadala ukugqwala.Okwesibili, uma insimbi engagqwali ihlangana nezinye izinsimbi, ikakhulukazi uma imanzi, isazogqwala.