Different fabrics require different methods of cleaning. Most curtains are too heavy and bulky to be cleaned at home. Professional cleaning is recommended.
If you live in the Auckland region I can personally recommend Curtain Clinic. They will even pick up and rehang your curtains after cleaning them. They can also repair and re-line damaged curtains if required - https://curtainclinic.co.nz/
Professional cleaning companies should understand the care required for your fabric. However, if necessary please contact McKenzie House for cleaning guidelines specific to your fabric.
There are some basics that apply to every fabric that can be done in your home to prolong the life of your soft furnishings:
To clean sheer/voile curtains:
Remove all hooks from the top of the curtains.
Gently handwash your sheer curtains in a bath of cold water or use a delicates cycle on your washing machine. You can add detergent or a very weak bleach solution.
Do not spin the curtains - hang them outside on a washing line to drip-dry.
When nearly dry, reattach all of the hooks and re-hang your sheers on your tracks. Any remaining creases will drop out over a few days (especially if drawn across the window on a sunny day)
To clean roller blind fabrics:
As above, gently vacuum with a brush attachment and low suction on a regular basis to remove excess dust.
Fly dirt and insect marks can be removed with warm soapy water and a damp cloth.
Never use abrasive or solvent-based cleaning products.