Your mask can still be used after the mask's antiviral function and comfort have decreased after the 30 washes. The comfort and protection that it offers you is of course no longer as good as with a new mask. So maybe it is time to replace it with a new one. You can dispose of or recycle the old mask as you normally dispose of or recycle your textiles. Either in the textile waste, if you have one, or in the normal household waste.