Often we get the occasional egg whites left over - during the weeks I have given recipes for the use of these, my soft-scoop ice-cream being the favourite, and let's not forget meringues, which once made can be stored almost indefinitely in an airtight tin - good for crushing up and adding to things, like Eton Mess: whipped cream mixed with chopped strawberries and crushed meringue.
Here is a recipe which can use up the occasional egg yolk, and don't forget to read the tips:

Made-in-Minutes Lemon Curd: makes two 340g pots
2 oz (50g) butter
5 oz (150g) caster sugar
zest and juice of 2 lemons (pref unwaxed)
3 rgge, plus 1 more egg yolk
If the lemons are unwaxed, give them a good wash under warm water to remove any coating. Dry well. Put the butter, sugar, zest and juice of the lemons in a bowl and microwave on full power for 1 - 3 minutes until the sugar has dissolved. Beat the eggs and the yolk together until smooth (don't not overbeat, you don't want bubbles). If you are aiming for a really smooth curd sieve the eggs to get rid of any albumen lumps. Stir the eggs into the butter mixture then return to the microwave and cook for one minute, then stir, and repeat for a total of 3 - 4 minutes (stirring after each minute) until the lemon curd has thickened. Pour into small clean hot jars. cover and keep in the fridge. Eat within a month.
Use left-over Lemon Curd as a sandwich cake filling, or fold into Greek Yogurt (equal quantities) and freeze to make a yogurt ice-cream.

Re-cycling Tips: Dip the lemon shells in salt and use to clean brass and copper. Rest your elbows in empty lemon shells, this softens the hard skin and also bleaches it. Soak the lemon shells in water and use for rinsing fair hair. Shred the shells finely and dry them in the sun (or in an airing cupboard or above a boiler etc) then add them to pot-pourri.
Crush eggs shells and pour boiling water over them. Leave to stand until cold, sieve and use the liquid to water house plants, it contains loads of minerals. Also sprinkle crushed shells around tender plants - helps to keep away slugs. Also said to be good, dug in around rose bushes. Crushed egg shells, put into decanters and swirled round with water help to clean the glass. Chefs use egg shells in their stock when wanting to make a very clear consomme (must look that one up).
Any butter left on the wrapper can be used to grease baking tins etc. If the butter paper is greaseproof, use to line baking tins (printed side down) instead of using new paper.
When emptying a bag of sugar, carefully undo the sealed bits and you should find you get an extra spoon of sugar which has been tucked into the folds. The bag can then go into the recycling bin.