Do you know what scents I can use (essential oils, incense) to ward off evil spirits?

lemon lime

There are no evil spirits. Scents wouldn’t scare them away if there were. Think about it, they are dead. I doubt they smell much. If you believe they can smell, I would just leave garbage all over the house, I know that would scare me away. You shouldn’t worry so much.

It is common to use sage sticks, called smudge for this purpose. That is fairly common in the intermountain west.
Frankincense has been used for this historically also.

Creating a calming mind and living space will work the best. Try some sandalwood incense and meditate everyday, even if just for 10 min a day. Focusing your mind on something positive will help keep away elements that affect the mind.

one bottle of crazy.

sage is typically used for this. but also remember, asking God to help you and telling them to leave in the name of Jesus, works better than the herbs he gave us, i would do both!

This is what I use. It is very general.
You can also wear or carry a black tourmaline.

PROTECTION OIL
4 drops Basil
3 drops Geranium
2 drops Pine
1 drop Vetivert

Mix the oils in 1/8 cup jojoba oil in a sterilized glass jar.
Wear for protection against all kinds of attacks.
Also anoint windows, doors, and other parts of the house, to protect it.
(I have also mixed it in 1/8 cup unscented skin cream- to carry along and apply unobtrusively at any time — I carry this one in my handbag)

You can also add the protection oil to a “florida water” wash, and then wash the floors of your home and/or business, to rid the environment of negativity and evil. You can also keep it in a spray bottle, for a quickie cleansing, between floor washes:

FLORIDA WATER
1/2 gallon 90 proof alcohol (grain or vodka)
1 pint spring water
1 tablespoon fresh squeezed lemon juice
10 drops protection oil

Best mixed during full moon, but you can do it any time, if you have an emergency.

You can also burn cedar incense in your house.

Western Gray Sage or Cedar smudge will help keep those things away from you that make you uncomfortable. If that doesn’t work the way you wish try Sweetgrass. I can say with pretty much confidence that there spirits out there, every belief says they are there.