Non shreddable foraging is quite easy as everything can be washed and refused.
It isn't limited to trays either - there are other options too to mix it up.
For trays it is super easy! Get your tray, something with a lip/raised rim, like the IKEA picnic plates, or a plastic flower pot plate, or a small stainless steel baking sheet, or a porcelain rabbit food bowl, any thing you have that can contain the things you want to include. And throw in a couple of handfuls of anything like small plastic beads or other toy parts, then sprinkle over some treats and voilà, easy peazy. If your using a bowl on the side of the cage (not on the cage floor) you should use lightweight plastic items, beads and other shapes - things that won't break or damage, or hurt anyone if thrown. If you will place the tray on the floor, you can use glass marbles.
Keep in mind that as much as we're talking about non shreddable, you could add in pieces of cork, sola or mahogany pods as they chip off in pieces, if your lovebird is Roseicollis they won't be able to take the pieces to build a nest. If your bird is Fischeri or Personatus I am unsure whether they will take it in their beaks.
Other options for foraging, foraging cups! Another suuuper easy one. Buy or make a foraging cup, add in some treats and hang it up. I like to move it around to keep it interesting. I have some I have bought from various places, I also have some I've made with toy parts, and if you're on a budget or stuck for cash, you can make a great foraging cup toy with just bottle caps and string (two caps facing each other, then a big knot or beads if you have them, then another pair of caps and so on - you can have a toy of 3 or 4 spaces and add in treats to just two and let the birds find them).
Another one, a foraging carpet/mat/rug whatever we're going to call it. You can buy these from various places especially Etsy, or you can make your own, they're so easy and fun to make ( I have made one for myself and also for a fellow member here).
Lay the mat down, sprinkle over treats and toy parts to play with.
There was a member who was active a while back (
@Wardy) and he used to get paper straws, cut into small pieces, then stuff a sunflower seed in some and then mix then into a tray. As the pieces are small, I think this would be ok for an activity that won't exasperate laying.
On top of these activities, you can include some non shreddable toys like SS toys, jingle jingle type toys, small cat balls, chippy pine toys (the ones that chip into bits not strips - you will have to observe how the wood is cut and which way the grain goes).