thanks for the helpful tips @jackie02
my lola always sell the plastic bottles that i have gathered.
when i was still working at a certain tv station, i collect plastic bottles that were thrown near the vending machine in our office. when the bottles were sold, we accumulated a hundred and fifty pesos. so after that, i made it a habit to collect plastic bottles and insist my friends or companions not to throw it away and donate it to me. very useful, indeed. 😉