Blocked drains? If your problem is in the bathroom it probably relates to either hair balls (we all lose abou 100 strands of hair when we shampoo which combines with soap residue to form a solid plug) or cotton waste in the loo. Use the liquid form of Drano to dissolve the soap residue so the hair can flow down the drain. Often you need to follow up the use of chemicals with a plunger to force the plug around the “S” bend so it can flow down the sewer when loose. In the case of a blocked toilet you might use a toilet plunger to create enough pressue to move the plug.
If the problem is in the kitchen it is probably it probably relates to a build up of grease and scraps causing a blockage. Use the crystaline form of Drano to dissolve the grease then follow up with a plunger as required. Sodium hydroxide (caustic soda) is the basis of drano so you can use that as a cheaper alternative. Do not ever use hot water to flush the pipes after using these products. Caustic soda can also be used as a cheap paint stripper or grease remover on exterior porous surfaces such as driveways.
If the problem is smell first check your drains are full of water. Water is in the S bend to block smells coming back up the pipes. If there is no water present simply re-charge the waste by pouring water into the drain.
If that is not the problem and the smell persists you will find a product called Actizyme helpful. Smell generally comes from bacteria. Actizyme is an enzyme that gobbles up grease and bacteria. Regular use of Actizyme as a maintenance product will help stop the problems before they start.
If all else fails use Sulfuric acid. That is the ultimate drain cleaner and is quite cheap. The use of Sulfuric acid causes a smelly mist so beware. It is also highly corrosive which is why it is often the agent of choice used by murderers to dissolve bodies. The acid should only be added to water and, once again, avoid the use of hot water.
You may need an eel to force the blockage past the S bend. There are many varities of eels available for purchase.
On the other hand if your problem relates to tree roots you may need a plumber to clear the obstruction with an eel or high pressure water jet. Many people who have old clay pipes use Copper Sulphate as a maintenance product to dissolve tree roots (without killing the tree above) penetrating into the pipes and collecting waste. You can first try to dissolve the tree roots by adding 1.5 – 2kgs of Copper Sulphate into the sewer to dissolve the roots but this can take a little time – but a lot cheaper than a plumber.
Ultimately the best way to ensure no tree roots get into the sewer is to replace the old clay pipes with PVC.