In February 2002, Ilse went to the United States and rented a small house in Nashville. She wanted to have another go at song-writing, but not the way they do it in Nashville. Many times, she told people that in Nashville, writing is a 9 to 5 job, with writers sitting in small rooms, constantly producing songs. This is not something Ilse likes to do; for her, song-writing is still about getting a good idea, writing it down and work it out later on. In the past year, she had written down some ideas for songs. In the U.S., she wrote some songs from these ideas with Blue Miller, who has played guitars on both Livin' on Love and World of Hurt. She also wrote some songs with Bruce Gaitsch, the infamous producer of Madonna's "La Isla Bonita". Bruce also produced Ilse's new album. Bruce Gaitsch is someone from "the LA scene", rather than Nashville and because of this, the musicians on Ilse's new album are really different from the previous two. For example, Vinnie Colaiuta plays drums on most tracks and guitar legend Michael Landau is also present.

After a year of writing and recording in Capitol Studio B in Los Angeles, CA, Clean Up was released on April 15th 2003. Ilse is (co-) writer of all songs on the album! In interviews, Ilse says that Clean Up is very autobiographic. This means that quite some bad things must have happened, because songs such as "Machine People" and "Clean Up" are definitely not telling a happy story. What's happened? Out comes that the story of the Livin' on Love Tour, although musically a great success, wasn't that big a success financially. Mistakes had been made and Ilse had had many worries about being able to pay her band, for example.

When Ilse was back in the Netherlands for a few weeks during writing, she appeared as a surprise guest in two concerts of the Dutch band Kane in Ahoy, Rotterdam. She sang a duet entitled "Before You Let Me Go", together with Kane's foreman Dinand Woesthoff. This song was later released as a single, which reached number one in the Dutch single charts!