Since this won't happen otherwise, I suspect...

SALES:

http://www.tf2outpost.com/trade/22418942 Sold for GE Bombing (Outdated at 2, mini at 1.85)

1.85 * 0.9 = 1.665 (rounding to 1.7)

Histories:

http://www.tf2outpost.com/item/440,2957402658,324,5

http://www.tf2outpost.com/item/440,2957402646,249,5

http://www.tf2outpost.com/trade/21607129 Sold for Gifted Miami Trilby (see mini at 2)

2 * 0.9 = 1.8

Histories:

http://www.tf2outpost.com/item/440,2843821756,324,5

http://www.tf2outpost.com/item/440,2843821738,324,5

Trilby mini:

http://www.tf2outpost.com/trade/21776382 Sold for DBD Larrikin (~2.2)

2.2 * 0.9 = 1.98 (rounding to 2)

Taking two, which is the value also suggested, near enough, based on Polar's suggestion in the duped / gifted hat thread.

Bombing Mini:

http://www.tf2outpost.com/trade/21884736 Sold for Vivid Hotrod (~1.9) + sweets (~0.2)

2.1 * 0.9 = 1.89 (rounding to 1.9)

Histories:

http://www.tf2outpost.com/item/440,2981911395,249,5

http://www.tf2outpost.com/item/440,2872999024,148,5

http://www.tf2outpost.com/trade/22215140 Sold for Stormy Tree (2)

2 * 0.9 = 1.8

Histories;

http://www.tf2outpost.com/item/440,2908881001,249,5

http://www.tf2outpost.com/item/440,2908880988,341,5

Using 1.8-1.9.