# The Pencils and Graphic Instruments (Safety) Regulations 1998, Paragraph 4


After shaking, the mixture shall be allowed to stand for one hour, and shall then be filtered. The resulting solution shall then be analysed.

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Source: https://www.legislation.gov.uk/uksi/1998/2406/schedule/paragraph/4 (the official version)
Page: https://openlegislation.uk/pencils-and-graphic-instruments-safety-regulations-1998/schedule/paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.