Turn the spa pump off. Turn the power off to the spa at the circuit breaker.
Snap off the lid covering the filter if it has a lid and slide the cylinder filter out. Your spa filter should be noticeable as you sit in the tub. Look in your owner's manual if you cannot locate the spa filter as the manual has a diagram of all the spa parts.
Place the spa filter in a tub or large container of water. Make sure the entire filter is submerged in water.
Pour 3 cups of white vinegar into the water. For extra removal power you can heat the vinegar before adding to the water, or use straight vinegar.
Allow the filter to sit in the solution for at least one hour. This gives the vinegar time to loosen debris encrusted on the filter.
Take the filter out of the water and vinegar solution and rinse with a garden hose.
Place the filter back in its normal position in the spa. Snap the lid back in place if it had one. Turn the power to the spa back on at the circuit breaker.