And finally an outlook:
In the latest "Präparator"-magazine there is an article (KRAUS, 2002) about the use of tensides in combination with other chemicals to receive an ideal etching result. They use a combination of 2% or 6% acetic acid, a non-ionic/ anionic tenside and hydrogen peroxide. They also tested several kinds of tensides in combination with various acids and came to the conclusion, that non-ionic and anionic tensides work best. This is definitely worth further investigation.

Supplier for Rewoquat W 3690 PG:
Goldschmidt Rewo GmbH & Co.Kg
Max-Wolff-Str. 7
36396 Steinau
Germany
phone: 0049-6663-54-0
fax: 0049-6663-54-129

References:
BLANK, ? (1990): Tuebinger mikropalaeontologische Mitteilungen.

KRAUS, Werner (2002): ATP Reagenz und Lamipeel .-Der Praeparator 48 (2): Hannover 2002

LIERL, Hans-Juergen (1992): Tenside - ihre Verwendung fuer die Praeparation geologisch - palaeontologischer Objekte.- Der Praeparator 38 (1): 11-17, Bochum 1992

RIEGRAF, W. (1985): Mikrofauna, Biostratigraphie und Fazies im Unteren Toarcium Suedwestdeutschlands und Vergleiche mit benachbarten Gebieten.- Tuebinger mikropalaeontologische Mitteilungen 3 (1): 1 - 210.

Thanks to:
Hans-Juergen Lierl for his information over the phone.

Lissy Lange (Biber)
Bayer. Staatssammlung für Paläontologie u. Geologie
Richard-Wagner-Str. 10 80333 München
Germany
email: pal.praeparation@lrz.uni-muenchen.de