Repair Fabric Alvo artek armchair 406  

Posting pictures of your chair & the stains will help you get more specific responses.  

You said linen fabric as in upholstery?  

I remember the Aalto model 406 having webbing (cotton/linen).  If the stains are old & has set for a long time, it may no longer come out but without seeing the stains you mention, it could just be discoloration from age, the natural light color webbing tend to do that overtime.  Some see that as flaws while others see that as a natural patina as the chair ages.  

If the webbing needs replacing, Artek or any authorized Aalto shops sell those new.

https://www.aaltousa.com/aalto-furniture-accessories.html

Thank you so much. I hope that my photo attached here, as I tried to do it earlier.