In eggs this is not called a blood clot, it is called a meat spot. I don't think there is a known fixable cure for them, if there was, the commercial growers would be doing it. They just happen. It is normal. Commercial growers have taught us that these are "bad" since they don't sell those eggs to the public. They sell them to places that make cakes and such. If it bothers you, simply take it out of the egg before cooking.
They don't bother me at all. I cook them and eat them just like any other bit of egg.
Are you talking about something that looks like this? This is a blood spot and is harmless. If it bothers you just scoop it out with a spoon before using the egg.
Blood Spots and Meat Spots
These are rarely seen in commercially produced eggs, as when the eggs are candled, those containing blood spots and meat spots are rejected. The eggs are still perfectly edible, but are rejected for aesthetic reasons. Blood spots are normally associated with the egg yolk. Rupture of tiny vessels during ovulation is typically the cause of blood spots. If you raise your own hens for eggs you may notice these from time to time.
Blood spots may appear on the yolk of some eggs, a by-product of ovulation
Meat spots are usually brown in color and are typically associated with the egg white. Because the albumen is deposited around the egg in the magnum of the oviduct, these spots arent due to vessel rupture at ovulation. They are formed when small pieces of the of the oviductal lining slough as the egg passes through.