One morning whenmata sita put sindoor on her forehead (maang).
At that time hanuman ji arrived there qnd asked mata sita that why she puts sindoor on her forehead everyday?
In her reply to the question of lord hanuman she smiled and told him that the sindoor dedicates to her husband lord rama. The sindoor is the sign of her unconditional love and respect towards her husband lord shri raama. So for that reason she always wears sindoor on her forehead everyday.  
After listened to mata sita lord hanuman pour sindoor over his body qnd came near to mata sita , when she asked why he did like that simply he replied to mata sita that i also love my lord rama unconditionally and he is always in my heart .so that i pour all of the sindoor on my body . 
After that day the devotees of lord hanuman offers sindoor and til oil on every Tuesday and Saturday to him and the sindoor is orange in color . 
And the til oil also offers to him for making diyas to worshipping and for his body. 
Hanuman sindoor is made-up of turmeric and alum and lime or with other herbal ingredients in the traditional way but in nowadays hanuman sindoor made up of vermillion an orange red color particular pigment the purified and powdered form of cinnabar, which is the chief form in which mercury sulfide naturally occurs.
For this reason some statues of lord hanuman looking red-orange color . 
The worshipers add hanuman sindoor to sesame oil and mix it and apply to the body of lord hanuman . 
It believes as if devotees offers sesame oil and sindoor to lord hanuman then he will impress with his devotees and fulfill all wishes and dreams and protect them from evil things. 
On his special day of lord hanuman ji Tuesday and Saturday all his devotees in morning after taking bath and wearing clean clothes offers sesame oil  diyas and vermillion/ hanuman sindoor to impress the lord hanuman. 
And chanting hanuman chalisha for lord hanuman. It fills positive vibe in our soul we feel like pure form inside. A happy positive feeling is comes from our heart and soul and we can easily forget our sorrowness . It fills energy in our soul, except that our home also fill with positive energy and all evil energy can not enter to our home . 
As the most powerful god every evil /asura and their negative effects afraid infront of lord hanuman.