Things you’ll need
Krylon Make it Acid-Free Spray
Acid Testing Pen
Vintage sewing pattern
Step 1
Mark an inconspicuous area of the vintage sewing pattern using the pH testing pen.
Step 2
Allow the mark to dry to determine whether or not acid is present on any parts of the sewing pattern: envelope, instruction sheet and pattern pieces.
If the initial mark dries any color other than purple acid is present.
Step 3
Spray the sewing pattern with Make It Acid-free. It dries in moments. The original marking will turn purple again. This is an indication acid the sewing pattern has been De-acidified.
Step 4
Store your vintage sewing pattern properly.
Here’s a reference video