No idea of your country but a 20Second google search revealed this;
To remove lice, it is recommended to use a mild pet insecticide, such as "Nuvan." After spraying the plumage, wait for 2 - 3 minutes and then gently ruffle the feathers over a white tray or plastic sheet to collect the lice which fall from the feathers.
I found that one great way to remove lice and mites from your birds is to sprinkle Sevin Garden dust under their wings and tail, and on the back. Check the birds the next day and if there are still lice present, repeat the process, as needed. I found Sevin dust [active ingredient: Carbaryl (1-napthyl N-methylcarbamate)] equally effective in getting rid of red mites
Avian Insect Liquidator is another way to get rid of mites, lice and other insects in the birds' environment. This all-purpose insecticide from Vetafarm contains a water-based insecticide that is harmless to birds but effective against insects.
Sanitize and treat the birds' environment (cages, perches, aviaries, nesting areas, etc.). Secondly, allow your birds to bathe daily. Most birds enjoy doing so and if you provide them with a shallow clean dish, they will usually be happy to bathe without encouragement. Some birds like to be misted, or even sprayed. Sprinkling Sevin dust underneath nest bowls and around nests will eliminate all kinds of insects.