Ford Focus 1.8 petrol (UK) COOLANT QUESTION?

When I was checking under the bonnet of my Ford Focus 1999 T which had been sitting overnight, I had a look at the coolant reservoir which uses the orange coolant. I have to say that the vehicle was on a slight upward slope so the level was only just above MIN. However I noticed that above the level of the coolant, on the side of the reservoir, was like an orange jellyish solid material presumably from where the coolant level would normally be. Is this normal ? The coolant is always kept at the correct concentration, but it has not been changed yet because Ford say that the orange coolant needs renewing after 10 years.