Salbutamol has been shown to improve muscle weight in rats  and anecdotal reports hypothesise that it might be an alternative to clenbuterol for purposes of fat burning and muscle gain, with multiple studies supporting this claim.     Abuse of the drug may be confirmed by detection of its presence in plasma or urine, typically exceeding 1000 µg/L. The window of detection for urine testing is on the order of just 24 hours, given the relatively short elimination half-life of the drug,    estimated at between 5 and 6 hours following oral administration of 4 mg. 
There is one interesting note regarding Albuterol that is worth mentioning. Athletes who perform in sports requiring a lot of cardiovascular activity have sometimes reported a better response due to Albuterol use. Makes sense, after all, this drug was designed to treat cardiovascular ailments; you know, such as breathing, something you do a lot of when you run. This evidence is however not conclusive due to theres simply no study available to prove it; with this information we are left with what we are so often left with in the performance enhancing world and often that is only word of mouth.