CLEANING SOLUTION

1 . A cleaning solution comprising

an organic acid comprising a compound of the formula

or a salt thereof, wherein G is selected from the group consisting of a bond, C 1-10 alkylene, C 2-10 alkenylene, C 2-10 alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene, and wherein each hydrogen atom in C 1-10 alkylene, C 2-10 alkenylene, C 2-10 alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene may be optionally substituted with one or more R N , wherein each R N is independently selected from the group consisting of—halo, oxo, —OH, —CN, —NO 2 , —CF 3 , —OCF 3 , —CO 2 H, and —NH 2 , and

a surfactant blend comprising a primary surfactant and a first co-surfactant.

2 . The cleaning solution of claim 1 , wherein G is a bond or —CH 2 C(OH)(CO 2 H)CH 2 —.

3 . The cleaning solution of claim 2 , wherein the primary surfactant comprises a compound having the formula

or a salt thereof, wherein a is an integer from 1-20, and Q is a bond or —C(O)CH 2 —.

4 . The cleaning solution of claim 3 , wherein a is 11 and Q is a bond.

5 . The cleaning solution of claim 4 , wherein the first co-surfactant comprises a compound having the formula

or a salt thereof, wherein each of b and c is independently an integer from 0 to 12, and d is an integer from 3 to 40.

6 . The cleaning solution of claim 5 , wherein d is 3 and the sum of b+c is 8 to 14.

7 . The cleaning solution of claim 5 , wherein d is 7 or 9 and the sum of b+c is 8 to 14.

8 . The cleaning solution of claim 1 , wherein the primary surfactant has a Hydrophile-Lipophile Balance (HLB) of at least about 15.

9 . The cleaning solution of claim 8 , wherein the first co-surfactant has an HLB selected from a range of about 12 to about 16.

10 . The cleaning solution of claim 1 , wherein the cleaning solution has a viscosity of at least 40,000 cps.

11 . A cleaning solution comprising

an organic acid, and

a surfactant blend comprising a primary surfactant having a Hydrophile-Lipophile Balance (HLB) of at least about 15, a first co-surfactant having an HLB selected from a range of about 12 to about 16, a second co-surfactant having an HLB selected from a range of about 6 to about 10, and an emulsifier.

12 . The cleaning solution of claim 11 , wherein the HLB of the primary surfactant is in a range of about 20 to about 45.

13 . The cleaning solution of claim 12 , wherein the primary surfactant comprises a compound having the formula

or a salt thereof, wherein a is an integer from 1-20, and Q is a bond or —C(O)CH 2 —.

14 . The cleaning solution of claim 11 , wherein the first co-surfactant comprises a compound having the formula

or a salt thereof, wherein the sum of b+c is 8 to 14, and d is 7 or 9.

15 . The cleaning solution of claim 14 , wherein the second co-surfactant comprises a compound having the formula

or a salt thereof, wherein the sum of b+c is 8 to 14, and d is 3.

16 . The cleaning solution of claim 15 , wherein the emulsifier comprises a compound having the formula

or a salt thereof, wherein each of w, x, y, and z is respectively an integer from 1-20, the sum of w, x, y, and z is a multiple of 20; and R is selected from the group consisting of C 10-20 alkyl, C 1-10 alkyl, C 10-20 alkenyl, C 2-10 alkenyl, C 10-20 alkynyl, C 2-10 alkynyl, C 10-20 heteroalkyl, C 1-10 heteroalkyl, C 10-° heteroalkenyl, C 2-10 heteroalkenyl, C 10-° heteroalkynyl, and C 2-10 heteroalkynyl, and wherein each hydrogen atom in C 10-° alkyl, C 1-10 alkyl, C 10-20 alkenyl, C 2-10 alkenyl, C 10-20 alkynyl, C 2-10 alkynyl, C 10-20 heteroalkyl, C 1-10 heteroalkyl, C 10-20 heteroalkenyl, C 2-10 heteroalkenyl, C 10-20 heteroalkynyl, and C 2-10 heteroalkynyl may be optionally substituted with one or more R M , and wherein each R M is independently selected from the group consisting of—halo, oxo, —OH, —CN, —NO 2 , —CF 3 , —OCF 3 , —CO 2 H, and —NH 2 .

17 . A method of cleaning a device, the method comprising

contacting the device with a first cleaning solution comprising a first organic acid and a first surfactant blend,

wherein the first organic acid comprises a compound of the formula

or a salt thereof, wherein G is selected from the group consisting of a bond, C 1-10 alkylene, C 2-  alkenylene, C 2-  alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene, and wherein each hydrogen atom in C 1-10 alkylene, C 2-10 alkenylene, C 2-10 alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene may be optionally substituted with one or more R N , wherein each R N is independently selected from the group consisting of—halo, oxo, —OH, —CN, —NO 2 , —CF 3 , —OCF 3 , —CO 2 H, and —NH 2 , and the first surfactant blend comprises a first primary surfactant and a first co-surfactant,

wherein the first cleaning solution has a viscosity less than about 10,000 cps.

18 . The method of claim 17 , wherein the method further comprises contacting the device with a second cleaning solution, wherein the second cleaning solution comprises a second organic acid, a second surfactant blend, and a thickening agent,

wherein the second organic acid comprises a compound of the formula

or a salt thereof, wherein G is selected from the group consisting of a bond, C 1-10 alkylene, C 2-10 alkenylene, C 2-10 alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene, and wherein each hydrogen atom in C 1-10 alkylene, C 2-10 alkenylene, C 2-  alkynylene, C 1-10 heteroalkylene, C 2-10 heteroalkenylene, and C 2-10 heteroalkynylene may be optionally substituted with one or more R N , wherein each R N is independently selected from the group consisting of—halo, oxo, —OH, —CN, —NO 2 , —CF 3 , —OCF 3 , —CO 2 H, and —NH 2 ,

the second surfactant blend comprises a second primary surfactant and a second co-surfactant, and

the second cleaning solution has a viscosity greater than about 40,000 cps.

19 . The method of claim 18 , wherein the device is contacted with the second cleaning solution prior to contacting the device with the first cleaning solution.

20 . The method of claim 18 , wherein the first organic acid is substantially the same as the second organic acid and the first primary surfactant is substantially the same as the second primary surfactant.