Dritz Air-erasable 24 hours - purple marking pen that disappears within 24 hours
Instructions: Always test marking pen on fabric you are using to be sure marks will completely disappear. 
Some fiber contents - fabric finishes or dyes (red and pink in particular) may not be suitable for use with this pen. 
1.Mark fabric lightly. 
2.Disappearing ink normally disappears in 24 - 72 hours. (Humidity and penetration of ink can alter timing.) 
3.Marks can be removed with plain water if desired. 
NOTE - Do not iron over marks or launder before completely removing with plain water. Some laundry products containing sodium hydroxide or sodium carbonate may set marks if they are not completely removed before laundering.