A mixture of ordinary cooking oil and methylated spirits is a very effective cleaner. The meths helps break down any build up of sap and the oil will keep your tools lubricated. You don’t need to use your best extra-virgin olive oil; any cheap vegetable oil will do. Use a 75/25 mixture of oil and meth, apply to all surfaces then use a scraper or wire wool to clean.
Disinfect your tools regularly. A variety of solutions can be used to spry or immerse the cutting blades into to disinfect them. A strong solution of household cleaner, bleach, tea tree oil, ammonia, rubbing alcohol. Chloride based solutions can corrode your tools by encouraging oxidation and rust. Solvent based products will strip out lubricants and should be used with caution.
Note: If you are using electric pruners care is needed, particularly if immersing in liquid, prevent moisture getting into the operating mechanism.
If you are wanting to prevent the spread of a plant virus, an anti-virile product is required. Seek specialised advice on the disease you are wanting to contain.
Sharp, well maintained tools will result in cleaner cuts which help prevent diseases entering the plant.
Larger cuts can be sealed and protected using a pasting product.
And remember to also keep footwear and clothes clean, remove pruned off material from the planting area and clean tools regularly.