4 sales

1) Morning Glory Hermes (51) + 2 keys ---> 53

https://backpack.tf/profiles/76561198382654640#!/compare/1548720000/1548806400

https://backpack.tf/profiles/76561198093799835#!/compare/1548720000/1548806400

MG Hermes sold for Haunted Ghosts Antarctic Eyewear (33) + Kill-a-Watt Snowcapped (16) + 2 keys

https://backpack.tf/profiles/76561198145132802#!/compare/1551484800/1551571200

https://backpack.tf/profiles/76561198093799835#!/compare/1547078400/1547424000

HG Antarctic Eyewear sold for $59.99 on 22nd of February, keys were $1.81

https://marketplace.tf/items/30977;5;u8

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

59.99/1.81 =~ 33 keys

KaW Snowcapped sold for 18 keys

https://backpack.tf/profiles/76561198192118853#!/compare/1546646400/1546732800

https://backpack.tf/profiles/76561198085852627#!/compare/1546732800/1546905600

https://imgur.com/aZ4pcBr

But there is a seller selling for 16 keys for 2 months... Better to take 16 instead of 18 I guess

33 + 16 + 2 = 51

2) 34 keys

https://backpack.tf/profiles/76561198112516663#!/compare/1550793600/1550880000

https://backpack.tf/profiles/76561198093824611#!/compare/1550793600/1550880000

https://gyazo.com/5b62cdeda5ffc44f36fe868f48894566

Thank you, AlgorithmHD

3) 36 keys

https://backpack.tf/profiles/76561198112516663#!/compare/1550880000/1550966400

4) Green Energy German Gonzila (32) + 6 keys ---> 38

https://backpack.tf/profiles/76561198177759574#!/compare/1550793600/1550966400

GE Gonzila indate, 32 keys

https://backpack.tf/suggestion/5c29ae18cf6c751c7a1c4701

32 + 6 = 38

No marketplace sales

https://marketplace.tf/items/30394;5;u18

Total: 34, 36, 38, 53

Excluding 53 and going with 34-38.