About 17 years ago my roommate brought some spoons from her family in America to Israel I am concerned that they might not have been strictly kosher. Even if they weren’t, would they be now? as for the last 17 years they have only been used for kosher milky only.

ב"ה Shalom, Although the spoons have not made the food that came in contact with them not kosher, since just waiting 24 hours after the last use, the absorbed taste in the spoon has a foul taste and does not forbid other foods, it does not make the use of the spoons permitted to begin with. Therefore, if you want to be absolutely sure that all is 100% kosher, you can simply make them kosher yourself. Take a pot which hasn't been used for 24 hours for milk or meat, which is also deep enough so you can immerse the spoons in a manner in which they are fully covered with water. Boil plain water in the pot until it boils to a degree in which all the water is bubbling. Immerse the spoons fully in the water with the help of some net which water can pass through and remove promptly. Upon removal rinse the spoons in cold water. This shouldn't take you more than 15 minutes. If you don't feel sure of yourself to do it properly, Pessach is around the corner and you can bring the spoons to one of the your local stationד of making dishes Kosher for Pessach and have it done there. However, there is one more thing to consider. It is possible that the spoons, (assuming they are made of metal) were not immersed in a mikveh either after they were purchased. So once you have made the spoons kosher take them to be immersed in a mikveh , but do not make a Bracha since it is only a doubt if they were immersed. All the best