Odonil has being flushing out all the bad odour from our surroundings since it has been introduced in the markets.It never leaves any traces of bad odour. Description says it lasts for around 45 days. Bt if we use it in summers it wont last more than 30 days. And in winters sometimes more than 45 days. The usage is as simple as that. just open the pack and hang it as long as it smells good. We get it in different odours. Lavander is my favourite! . It smells so beautifully that u start feeling fresh and live.