Thin the glue with water or better yet, get Modge Podge. Our preschool used that for just about everything. YOu can find it at Walmart craft section or Michaels.

if you use corn syrup mixed with a small amount of water (and food coloring if you’d like to use this as the paint), it dries unsticky and looks shiny and feels really cool.

You can make a glue/water mix about the consistency of buttermilk, maybe a little thicker, then brush it on – can’t give you the exact mixture because it would depend on the consistency of the glue you use (all are not the same and also change with age). Just add a little water at a time and shake or stir as you go till you get the desired consistency.
NOTE : Even after your glue/water sealant is applied and dried, it will still get sticky if it gets damp….so let your students and parents know.
I did this when teaching kindergarten.

Thin the glue down with a bit of water. To be safe, make a sample to make sure the glue/water sealant doesn’t ruin the project.

I’ve used a rough ratio of 2 parts glue to one part water for projects around here.

eggs…..egg tempora?