Cut off any visibly infested stems or leaves with gardening shears. Place cut pieces in a sealed plastic garbage bag and discard.
Fill a 5-gallon bucket with warm water. Add insecticidal soap according to the package directions.
Cover the soil of the plant pot with aluminum foil. Hold the foil in place with one hand and turn the plant pot upside down.
Dunk the foliage of the plant into the bucket. Submerge as much of the foliage and stems as you can. Move the plant up and down two or three times so the water reaches all sides of the foliage.
Pull the plant out and sit it upright to dry. Remove the foil.
Cut off any infested foliage with pruning shears. Prune any dead foliage or branches, which can hide insect populations.
Spray the ivy plant with a strong spray from a garden hose, three times a day, every other day for a week.
Cover any visible scale insects with horticultural oil to smother them. Scale looks like a waxy bump on ivy plants.
Spray the foliage with an insecticidal soap according to the package directions to kill any remaining insects not removed by the water spray.