Kwindawo yokhuphiswano yeshishini leekhemikhali kunye neplastiki, ukukhutshwa kwemibhobho eqinileyo ye-PVC yinkqubo ebalulekileyo. Ukubandakanywa kwezisongezo ezithile ngexesha le nkqubo kunokuphucula kakhulu iimpawu zemveliso yokugqibela. Ukuqonda ukuba umbhobho oqinileyo we-PVC usebenze kangakanani kubavelisi abajolise ekuphuculeni umgangatho wemveliso kunye nentengo ukusebenza. I-PVC eqinileyo,