No they aren't reusable, the reusable ones are a foam type construction similar to mushroom filters and use a light machine oil to trap the particles, you can wash them out and then spray a light coat of oil back on them so they don't lose performance.
The cosworth filter is a similar construction to the stock yellow fibre type. They use a much finer weave than the stock ones and have a larger surface area to improve the filters performance. They get gummed up over time and can't be washed out, so you have to replace them as part of the normal service routine.