Take salt in a bowl and used lemon. Sprinkle salt over lemon/dip lemon into salt and rub this over the copper vessel. Keep squeezing the lemon so that lemon juice will mix with salt.
Keep turning the bottle/copper vessel and rub till until you cover the copper vessel completely.
If you are cleaning copper bottle, remove rubber from the lid and clean it with a brush.
To clean a copper bottle from the inside, put vinegar, hot water, salt and few lemon slices into the bottle. Shake well and keep till 10-15 minutes.
After 10-15 minutes, you can clean the bottle/copper vessel with your regular dishwashing powder/liquid. Again, for cleaning the inner portion, you can use bottle cleaning brush as shown in the video.