The results of our price comparison reveals this month's cheapest and priciest places to shop for groceries. A plunger and and bit of arm action! Fill the sink with very hot water and leave it for one to two hours the weight and pressure of the water may clear the stoppage if not, use a plunger to force water through the clog and possibly dislodge it. Boiler problems? talk to frank! Upgrade to a new ‘a’ rated gas boiler and start saving on your energy.