Please tell me if it is safe to debride/ scale my own teeth at home?

NO. : See a dentist. You can damage your teeth and gums by doing this yourself. Go to a dentist

Not really: Can you be sure you cleaned every nook and cranny? No. Can you treat your gum disease if present? No. Can you check for cavities? No. Can you monitor your periodontal health? No. You're trying to save money, after neglecting your teeth for a while, only to risk loosing them. Have a dentist treat you and this way you can give yourself every chance to keep your teeth for a long, long time.

Self treatment: Even if you are a dentist, you won't be able to do it well. I am a dentist and therefore certainly able to try to do this on myself. However, I have my dental hygienist clean my teeth. She can do it more gently and efficiently than i could ever do it on myself. It would not be safe, effective or smart on your part.