Sforno on Numbers 17:2/ספורנו על במדבר י״ז:ב׳

1ואת האש זרה הלאה, not on the place where the remains of burned offerings were stacked on the altar. The reason was that it was incense that should never have been allowed into the precincts of the Tabernacle.

2כי קדשו, for only the pans had become holy so that they could not be treated with disrespect.