After a while you may find that the cement seal at the base of your fluepipe, where it fits into the stove flue outlet collar, has cracked or crumbled, possibly due to the slight shifting in the balance of the stove as you open and close the door over many months. It will also probably have lost some of its colour depth and become an unsightly light grey.
Always follow the fire cement manufacturer's instructions, particularly regarding health and safety, such as exposure of the product to your skin and the use of personal protective wear. We recommend only buying a small tub of fire cement as this will be sufficient to do most fire cement repairs on a typical stove installation because the reality is, like putty, it's never going to be any good when you return to it at some later date.
When the stove is cold remove any of the easily removed fire cement pieces. You can use a small screwdriver to help you pick some of this out being careful not to chip the vitreous enamel on the flue pipe. Vacuum around the seal to remove any residue dust and fire cement pieces etc. Ensure that the stove lid and collar, as well as the flue pipe, is protected before you apply the new fire cement. Use masking tape around the top and bottom of the seal so that the fire cement can be applied with a neat straight edge. Do not allow any unwanted fire cement to dry out on the stove or flue pipe surfaces as this may be extremely difficult to remove afterwards. Where you have a mix of new black and old grey fire cement in the joint, if you prefer, leave the masking tape in place and use heat resistant spray paint, being careful to protect the stove lid and any other surfaces, to spray it all black.
Allow the fire cement to completely dry out as instructed by the fire cement manufacturer before you use the stove again.