Making a salicylic acid spray at home is relatively simple. Salicylic acid is a beta-hydroxy acid that is commonly used in skincare products for its exfoliating and acne-fighting properties. Here's a step-by-step guide to making a salicylic acid spray:

Ingredients:
- Distilled water
- Salicylic acid powder (available online or at some pharmacies)
- A spray bottle
- Optional: Witch hazel or aloe vera gel (for additional soothing properties)

Instructions:
1. Start by sterilizing your spray bottle to ensure cleanliness. You can do this by washing it with hot, soapy water and rinsing it thoroughly.
2. Fill the spray bottle with distilled water, leaving some space at the top for the other ingredients.
3. Measure out the appropriate amount of salicylic acid powder. The recommended concentration for a salicylic acid spray is typically between 0.5% and 2%. Start with a lower concentration if you have sensitive skin and gradually increase it if needed.
4. Slowly add the salicylic acid powder to the water in the spray bottle. It is important to add it gradually and stir well after each addition to ensure proper dissolution.
5. If desired, you can add a small amount of witch hazel or aloe vera gel to the mixture for additional soothing and anti-inflammatory effects. This step is optional but can be beneficial, especially for those with sensitive or acne-prone skin.
6. Once all the ingredients are added, close the spray bottle tightly and shake it well to ensure that the salicylic acid is thoroughly mixed.
7. Your salicylic acid spray is now ready to use. Before applying it to your face, make sure your skin is clean and dry. Spray a small amount onto a cotton pad or directly onto the affected areas of your skin. Avoid contact with the eyes and mucous membranes.
8. Start by using the spray once a day, preferably in the evening, and gradually increase the frequency if your skin tolerates it well. It is essential to monitor your skin for any signs of irritation or dryness and adjust the usage accordingly.
9. Remember to always follow up with a moisturizer and apply sunscreen during the day, as salicylic acid can increase skin sensitivity to the sun.

Note: It is important to patch test the spray on a small area of skin before applying it to your entire face, especially if you have sensitive skin or are prone to allergies. If you experience any adverse reactions, discontinue use immediately and consult a dermatologist.