Assuming that you are working only with properties reportable to the State of Colorado, this information is from the Great Colorado Payback general reporting page:
ALLOWABLE DEDUCTION
Except for aggregated amounts, you may, by law, voluntarily deduct and retain from each item remitted 2% of the value of the property you are remitting, or $25.00, whichever is less (L). For some types of property you may deduct and retain 2% or $25.00, whichever is more (M). Please refer to Property Code/Property Description & Dormancy Period Chart for eligible property types. The amount deducted from each item cannot exceed the amount due the owner. For instance, if the amount due the owner is $10.00, you cannot retain $25.00, the amount you would retain is $10.00.
Note: Holders may not retain the allowable deduction for properties associated with states other than Colorado.
Also note: Safe-Deposit/Safekeeping items are not eligible for deductions under this provision.
The full text of Colorado's Unclaimed Property Act, which has much more detailed descriptions of how fees can be charged on dormant accounts, can be found here:
http://www.colorado.gov/treasury/gcp/images/upa.pdf