from The Century Dictionary and Cyclopedia
- n. Same as escoba.
Sorry, no etymologies found.
Our dictionary agrees that the word is escobilla (which is also used for a windshield wiper blade).
It probably is escobilla as shown below, (copied from my on-line dictionary). brush
The hospital also is to receive the rights of _escobilla_  and the sweepings in the founding of metals.
The Philippine Islands, 1493-1803 — Volume 02 of 55 1521-1569 Explorations by Early Navigators, Descriptions of the Islands and Their Peoples, Their History and Records of the Catholic Missions, as Related in Contemporaneous Books and Manuscripts, Showing the Political, Economic, Commercial and Religious Conditions of Those Islands from Their Earliest Relations with European Nations to the Beginning of the Nineteenth Century