It's thought that older, more established plants can tolerate infestations. Regularly tending to plants and practising good housekeeping in the garden will give plants a better chance at survival.
Badly infested branches may be pruned and removed and disposed of sensibly.
Lighter infestations may be rubbed or picked off with hands.
Alcohol-soaked cotton and neem-based leaf shine may be rubbed over the surfaces of the areas infested. Initially, target the main points of infestation (70% of solution) and give a light coating to the whole plant (if small enough). From then on, spot treat plants every day.
Capturing natural enemies and releasing them on the affected area may improve infestations. These include insects like ladybirds, hoverflies, lacewing and earwigs. Likewise, by letting parts of the garden 'grow wild' paired with an abundance of pollinator-friendly plants, you can attract the latter into your garden.
Insecticidal soaps can be advantageous if applied regularly over several intervals. Use a drop of washing up liquid with a few more drops of vegetable oil, dilute with water.
Horticultural oils may be used as the next alternative. They are oil-based and environmentally benign, and these will give some coverage over adult stages. Oils can burn plants in direct sunlight, so read bottle instructions carefully.
If ants are also present at the site, these may be providing some protection to the scale. These can be controlled using a product such as Tanglefoot Pest Barrier. This will hopefully present a barrier for the ants that are attempting to reach the scale.