Four to six weeks before first frost, tidy plants by removing any dead, damaged, or diseased parts. Clean snipper blades with rubbing alcohol between cuts.
Plants
Apply insecticidal soap to any visible bugs following product instructions.
When soap is dry, give plant a bath by submerging it in tub of warm water with (optional) dose of insecticidal soap (see product instructions for amount). Add brick or rock over root ball if needed to weigh it down. Wait 30 minutes.
Gently wipe leaves with cotton rag to remove any dust or grime.
Replenish potting mix and/or move to larger pot if needed.
If there is time before temperatures get below 60°F (15°C), keep plants in a sheltered location outdoors away from other plants for 1 to 2 weeks to monitor for bugs.
Reapply insecticidal soap per instructions as needed.
When ready, move plants indoors to sunny location. Isolate from other houseplants if possible to further monitor for bugs for a few weeks. Reduce watering and stop fertilizing according to individual plant needs until growth resumes in spring.
Notes
See the article How To Bring Plants Indoor For The Winter for a list of suggested plants and more details. Not all plants are suitable for all of the steps shown. Decide on a plant-by-plant basis what's best for your plants.