Household toilets are anchored to the floor by two bolts that attach to a flange beneath the base of the toilet. The steel bolts are usually brass plated to resist rust in damp bathroom environments. Left exposed, though, the bolts and the nuts that secure them to the toilet will corrode from moisture and cleaning chemicals. Toilet bolt caps prevent this by covering the hardware with a waterproof dome-shaped seal. In addition to protecting the screws, they make the toilet easier to clean and give it a more finished appearance. Typical installation takes only a few minutes.
Clean the toilet flange bolt threads with a damp cloth or steel wool. If they're rusty, apply a few drops of light oil.
Check the length of the exposed flange bolt to ensure the cap is deep enough to cover it. If it's too long, cut off the excess with a hacksaw or snap it off at the indented area.
Remove the nut from the flange bolt by turning the nut counterclockwise with a wrench. Remove any washers beneath the nut.
Press the snap-on cap insert over the bolt with the lipped side up. Replace the washers and install the nut.
Snap the toilet bolt cap onto the insert.