Sputum can be disinfected by all except-

Sputum is best received in gauze or paper handkerchief and destroyed by burning.If the amount is considerable it may be disinfected by boiling or auto claving for 20 minutes at 20 lbs pressure.Alternatively the patient may be asked to spit in a sputum cup half filled with 5 percent creosol.When the cup is full it is allowed to stand for an hour and the contents may be emptied and disposed off.(refer pgno:130 park 23 rd edition)