If you have been arrested, or are in the process of being arrested, it is extremely important to maintain all of your legal rights. Everyone knows that a person being arrested has the right to remain silent, your Miranda Rights. So, do not talk to the police.
Also, the police may request permission to search your vehicle or property. Always say no even if you believe there is nothing illegal that they will find.
Lastly, they may ask you to sign a piece of paper concerning anything that they have seized. Chances are, this is a forfeiture (to them) of any property they have taken from you. If you sign this, they will own your property and chances are there is nothing you will be able to do about it. So, definitely do not sign.
By refusing to sign, you are forcing the District Attorney to request a hearing before a Judge to determine if they can keep your property. If your property was not illegal, the Judge will probably make them return it.