The park rangers in Yellowstone tell you not to put garbage in the geysers.
Even the non-active ones.
Ear Spring geyser is normally docile. It hasn't had a major eruption since 1957. But it had one September 15.
All kinds of garbage came out. They are still cataloguing the haul. (Including a baby pacifier from the 1930s, so that must have been missed somehow in the 1957 eruption.)