Thyme to Sow
If you plan to start seeds indoors you've most likely seen the toilet paper tubes or egg carton planters or even just the egg shells themselves being shared as nifty planting vessels. Let me warn you, after so many watering's, these paper based liners break down pretty quick and become quite unstable for transplanting...even rotting faster than your seedling can grow!
And as far as the egg shells go, you're going to have to crack them eventually so the plant can put on size, risking damage to the young roots. As darling as this method appears the truth is egg shells take years to break down in the soil....which is why they get crushed with my boot when I throw them into the compost. I have tried it all, so I know from experience.