An allergy test should be performed on the skin before every color application. To receive a free allergy test sample with instructions, please send a self addressed stamped envelope with sufficient U.S. postage ($5 US dollars) for The Netherlands.Be sure to include a request for the allergy sample you wish to try and an email address in case we need to contact you.Enclose this self addressed/stamped envelope in another envelope and mail to: Ecocolors Inc. 4760 Hammermill Rd #106 Tucker GA 30084