Based on that, I can see two possibilities: the first, Maxwell's memories are trapped in his subconscious, and those objects letting them escape the conscious barrier. The second is that the memories where indeed taken, and stored as spiritual energy within said items: however, I will warn EXTREME caution should this be true. If the items were of personal important before he lost his memories, it's a good possibility that Maxwell provided them himself. Most beings that steal memories would do so to consume their spiritual energy, not store them in the personal items of the victim, as such a thing would require preemptive action. This, of course, would point to something that Maxwell did not want in those memories.
I am merely hypothesizing, of course, and Maxwell, I am not questioning your resolve to recover your memories, for better or for worse. If you have one of those items that refreshed some of your memory, my eyes would most likely be able to determine whether any knowledge or spiritual energy was stored in them.
- Wycliff, the Seeker of Spirit.