I've been working on a couple old embroidery quilts that have been pre-stamped in blue for the embroidery and quilting lines. I did some research to determine how best to get the blue markings out. This is what I found ---------------
WASH the finished quilt: Hopefully you have access to a large capacity washing machine. Run a full cycle through your empty machine using lukewarm water no soap - this will clear out any residue of washing detergent usually used in it, and ensure your wash will be pure and clean. Having obtained an oxygen based product such as oxy clean or a cleaning agent specifically for vintage quilts and linens, fill your tub after adding the agent with WARM (comfortable to the skin) not cold and not hot water and agitate to disperse the washing agent through the water.
Immerse the quilt in the water and gently push it down to be sure it is totally wet. Agitate on ‘gentle’ for a few minutes. Stop the machine and soak for 15 minutes to a half hour. Drain machine and refill with WARM water, soak and run the agitate cycle on gentle again. Allow the machine to go on to rinse and completely turn itself off. Carefully supporting the wet/damp quilt from underneath – bending over the tub slide your arms under the quilt and lift it from below – never suspend a wet quilt as the stitches can/will break and damage the quilt. Make sure your clothing is well worn so that it will not transfer dye to the quilt if you hold it against your body.
Transfer carefully to the dryer on gentle/warm setting and dry to damp dry. Do NOT use a dryer sheet and do not over dry! Carefully remove and fold finished side out and hang a clean white towel over a door or your shower rail and lay the folded quilt on top of the towel – let it air dry while folding and refolding to allow for even drying and be certain that the quilt is 100% dry before removing it.
Examine the quilt in a clean dry surface to assess whether you still have an unacceptable residue of blue ink. In my experience, at most I’ve had to wash the item once more – never more than that.
Put your treasure on your bed and enjoy!