paper 4 months banana peel 5 months orange peel 1 year wool sock 1.5 year drink box without aluminum foil (kefir, fresh milk) 7 years cigarette butt with filter 15 years can 15 years plastic bag or bag 25 years (new ecological bags with self-decomposable degradable plastic 1 year) chewing gum 50 years plastic cup 70 years PET bottle, plastic bottle 100 years aluminum foil or tetra-pak with aluminum foil 100 years disposable diapers 250 years glass thousands of years (but maybe never) polystyrene tens of thousands of years (but maybe never) Source: Krasec.cz, Ekolist.cz, Fred13.blog.cz