Best left to a good gunsmith. Depending on exactly what you have, you could devalue it with improper cleaning.
Here is a good page on how to field strip and clean the colt 1911 pistol. http://www.bobtuley.com/45/magazine1.htm
45 ACP
That Colt .45 government model was made in 1918.
not much. the 1911 was made for the military. The 70 was a later commercial model of the 1911
Your Colt model of 1911 dates to the year 1918,with the serial number that you have supplied.
Any manual for a Colt 1911 will do.
Your colt model 1911 commercial (that is what the C stands for ahead of the serial number) was made by colt in 1917.
1917
1918
When made.
1944 & 1945
A Colt government model with that serial number was made in 1918.