I bought a cake for my daughter's birthday and I was trying not to waste anything. So I decided to use the cake platter and clear plastic lid as a mini greenhouse. I can start some of my perennials in January, so by mid June I should have quite a bunch of plants to plant.
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We occasionally purchase cakes from the grocery store deli that come with those plastic domed lids. I saved the last couple, sure I could figure out something useful to do with it. Well, I realized they make great heat savers for your plate of food if you're not quite ready to eat. Also, they would be great for summertime to place over plates and avoid bugs on your food. These are both things that have come in very useful for us, hopefully they will for you too. :)
When making a large salad to carry to a potluck dinner, use a plastic cake server, turned upside down. I did this for a seven layer salad.