A na-ekewa ájá nwere ụcha ka ọ bụrụ ájá nwere agba eke, aja nwere agba agba, na ájá nwere agba.Njiri mara ya bụ: agba na-egbuke egbuke, nguzogide acid na alkali, nguzogide UV, na enweghị nkụda mmụọ.
Ụdị: aja agba eke, aja aja.
nha: 10-20.20-40.40-80.80-120.120-180.200mesh.